Meredith Grey is a surgical intern at the prestigious teaching hospital Seattle Grace Hospital. She recently moved back to Seattle after her mother, an industry refining surgeon, was diagnosed with Early Onset Alzheimer's.
Meredith's new job introduces her to what appear to be her only friends. She is immediately close with Cristina Yang, and soon invites George O'Malley and Izzie Stevens to live with her. Alex Karev is on the fringe of the group, as he rubs many of his co-workers the wrong way. Cristina comes off as cold, Izzie is objectified for her looks and past as a model, and George has a crush on Meredith. The five work directly under Dr. Miranda "The Nazi" Bailey, a strict fourth year resident.
Romantic relationships run rampant in the hospital, as does syphilis. Meredith has a one night stand with a stranger, who ends up being her new boss, Dr. Derek Shepherd, Head of Neurosurgery. He actively pursues her, eventually resulting in a relationship. Cristina ends up pregnant after sleeping with Head of Cardio thoracic Surgery, Dr. Preston Burke. Both of these relationships call into question Shepherd and Burke's ability to remain impartial when giving interns OR time and make their relationships and their work lives much more complicated. George and Alex both sleep with Olivia the nurse, giving George syphilis and earning him the nickname "Syph Boy" which is only half a step up from his other nicknames "Bambi" and "007 (Licensed to Kill)".
The interns and their bosses work to save lives, often facing extreme and unlikely medical situations. Each case and patient reflects some aspect of the doctors' personal lives, and each save or loss shapes a part of their career or personality. The interns must deal with being on the bottom of a well established hierarchy, where The Chief of Surgery, Dr. Richard Webber has final say in everything.
The season ends with Meredith and Derek's tentative relationship being struck down by the arrival of Addison Shepherd, the wife that Derek never mentioned to Meredith.
Meredith struggles to deal with her mother's Alzheimer's worsening and her relationship with Derek being publicly blown apart. She has to readjust to her new role as "the other woman" and "the mistress".
Cristina has an ectopic pregnancy, and ends up losing the baby and needing surgery. Her relationship with Dr. Burke also ends up going public in this season. Burke is shot and his career is put in jeopardy. Dr. Bailey also reveals that she is pregnant, and ends up giving birth on the same day that her husband is in a near-fatal car crash and a patient with a bomb in his chest ends up in the OR.
Derek and Addison attempt to work out their marriage, by having Addison move into Derek's trailer. Addison hates the trailer, but puts up with it for Derek. The two of them take in Meredith, Izzie, and George's dog Doc, because he has too much energy to be cooped up in Meredith's house all day.
Meredith begins having a lot of new boyfriends in an attempt to get over Derek. She sleeps with George, which causes a lot of problems in their friendship. She ends up dating Finn the veterinarian after Doc gets cancer and has to be put down. The season ends with Meredith cheating on Finn with Derek.
Izzie falls for a patient, Denny Duquette, and risks the jobs of all of the interns to raise Denny's status on the list for organ transplants. Denny asks Izzie to marry him, and she agrees, but he dies suddenly in the season finale.
The season has more complex and interesting surgeries, from a bomb in a patient's chest, to a man who appears to be pregnant, to a train crash that causes mass casualties.
Izzie mourns Denny and finds out that Denny was very rich and left her 8.7 million dollars after his death.
Meredith and Derek rekindle their relationship. Meredith nearly drowns, waking up after a near death experience to learn that her mother has passed away. Their relationship is complicated by Derek's fear that Meredith didn't actually want to live.
Cristina helps Burke hide his tremors. Cristina agrees to marry Burke, but he leaves her at the altar after realizing that Cristina is only marrying him because he wants her to, not because she wants to. This is the breaking point for Meredith and Derek's relationship as well, as Meredith no longer believes that people like her and Cristina can have love.
George's father dies, prompting him and Callie to elope in Vegas. Their marriage quickly falls apart when George and Izzie have an affair.
The death of Meredith's mother prompts her step-mother Susan Grey to create a relationship with Meredith. Meredith is initially reluctant to accept the care, but soon becomes very fond of Susan. Susan dies after a surgery complication, wrecking the fragile relationship between Meredith and her estranged father.
On a professional level, everyone is under pressure. The interns have an exam that they must pass to complete their intern year and become residents. Meredith has to retake the test after having a mental break, and George doesn't pass the test. He must make the decision to leave the surgical program and move to an easier program or retake his intern year.
The four main attendings, Derek, Burke, Mark, and Addison, compete to replace Richard as the Chief of Surgery. Mark is dismissed for being immature, Burke is ruled out due to covering up his injury, and Addison is dismissed because the job is her only reason to be in Seattle. Derek is offered the job, but turns it down, giving the position back to Richard.
Addison leaves the show to start the spin-off Private Practice, and Burke leaves to avoid facing Cristina.
The new residents begin teaching new batch of interns which include George who decided to repeat his intern year and Meredith's half-sister Lexie. The doctors work to live up to their new responsibilities, but have trouble balancing their responsibility to teach and their hunger to perform surgeries.
Callie and Mark have a friends-with-benefits relationship going, but Callie develops romantic feelings for the new Chief of Cardio-thoracic surgery, Erica Hahn. The realization of these feelings allows both women to recognize their sexuality. Erica realizes she's been gay her entire life, while Callie realizes that she is bisexual and attracted to both men and women.
George redoes his intern year, becoming friends with the other new interns, including Lexie. This causes some tension between George and his friends. Alex's girlfriend, a former patient, is admitted to a psychiatric facility for a personality disorder. Cristina tries to move on from Burke.
Derek and Meredith continue to meet up, even though they are no longer together Derek starts dating Rose, a scrub nurse, ending his personal relationship with Meredith. On a professional level, Meredith is helping Derek on a clinical trial operating on "inoperable" brain tumors. They lose twelve patients before finally having success. This success brings Meredith and Derek back together as a couple and strengthens their working relationship.
Cristina develops a relationship with the new trauma surgeon, Dr. Owen Hunt. Mark and Lexie begin a new relationship. Callie starts exploring a relationship with pediatric surgeon, Dr. Arizona Robbins. She struggles with her sexuality and figuring out what she wants in life, which puts strain on their relationship.
The hospital is only ranked twelfth, which puts pressure on Richard and the board to step up the hospital's reputation. The interns don't feel that they are being taught properly, so they start performing simple procedures on each other. This goes badly when they attempt to take out Sadie's appendix and something goes wrong, putting her life in danger. Part of this lack in teaching is due to the fact that the residents are doing their first solo surgeries and don't want to share with the interns.
Izzie thinks she's seeing Denny's ghost, but soon realizes that she's hallucinating. She diagnoses herself, then takes the opportunity to have her interns diagnose "Patient X". She confirms that she has an aggressive Stage IV melanoma that has spread throughout her body and into her brain. She has to undergo multiple surgeries and aggressive IL-2 chemotherapy.
Meredith and Derek get engaged and plan to get married. Izzie requests to plan the wedding and uses her cancer to get her way on everything. They decide to give their wedding to Izzie and Alex because Izzie is probably going to die. The two "tie the knot" on a post-it note between surgeries.
George, now a resident, discovers he's good at trauma and is inspired by a patient to join the army as a trauma surgeon. The other doctors think that he's going to be killed and react badly. The season ends with George being hit by a bus and in critical condition and Izzie recovering from her brain surgery but her heart suddenly failing. Izzie has a dream that she's in the elevator the night Denny dies, but when the doors open George is wearing a military uniform.
The season begins with the doctors confirming that John Doe is really George O'Malley. He dies and his death takes a large toll on most of the hospital, but especially the doctors who were close to him.
There are rumors that the Hospital Board wants to replace Richard with Derek, but Derek warns Richard, giving him the chance to make plans. Richard proposes that Seattle Grace merge with the other main hospital in Seattle, Mercy West Medical Center. This brings in new doctors, but there isn't enough jobs for everyone, causing a lot of tension between the newcomers and the original doctors.
Meredith's father needs a liver transplant, but because he's a recovering alcoholic he isn't eligible to be on the transplant list. Meredith donates part of her liver, even though she doesn't have a relationship with her father, because she knows that Lexie would be crushed by her father's death. This puts her on bed rest for a while, leaving her out of the direct drama surrounding the hospital merge.
Derek performs the most risky and complicated surgery of his career. He operates on an inoperable spinal tumor and ends up drawing it on the wall below the marriage Post-It.
Izzie is fired in the merger, and eventually divorces Alex. She stops coming to her IL-2 appointments and leaves to work at another hospital. Alex ends up shouldering her medical bills.
Mark finds out that he has an eighteen year old daughter named Sloan and that she's pregnant. He gives her a lot of help and wants to be in her life and the baby's life but she decides to give the baby up for adoption and go back home with her mother. The existence of Sloan puts a strain on Mark's relationship with Lexie, who ends up dating Alex. Mark ends up briefly dating Teddy, the new Head of Cardio-thoracic Surgery.
Dr. Teddy Altman is invited to Seattle Grace Mercy West by Owen, who she was best friends with in Iraq. He invites her there so that Cristina can have a new cardio-god. She ends up causing problems in their relationship though because she is in love with Owen. Cristina is so career driven and values Teddy's knowledge so much that she offers Owen in exchange for Teddy staying.
Derek finds out that the Chief is an alcoholic and goes to the Board. The Board makes Derek Chief, like he wants. Derek promises Richard that if he goes to rehab he will eventually be able to come back to the hospital. Derek becoming Chief makes Meredith upset for going behind Richard's back, but she ultimately supports him as her husband. He ends up hating the job because he misses actually being in the OR.
The season ends with the husband of a patient coming to the hospital with a gun and shooting doctors and other hospital staff. The three main targets are Derek, Lexie, and Richard. Richard and Lexie are unharmed, but Charles and Reed are killed along with other unnamed staff, and Alex, Owen, and Derek are shot. The stress of the shooting causes Meredith to suffer from a miscarriage.
The doctors are all reeling from the shooting, and have mandatory therapy and must be cleared by a therapist before they are allowed back into the OR. The shooting prompts Cristina and Owen to get married. Cristina suffers PTSD in the OR due to the shooting and it takes her a long time to do what she loves again.
Meredith and Derek try to have another baby, but find out that Meredith has some fertility issues and that it's unlikely. She reacts badly to some of the drugs they give her and has some vision problems that almost cost her in the OR.
Arizona goes to Africa to help little kids who can't get the care they need, ending her relationship with Callie. Mark tries to get back together with Lexie, but ends up sleeping with Callie because she's upset about Arizona leaving. Arizona comes home early because she misses Callie and finds out that Callie is pregnant with Mark's baby. The three of them decide they all want to be involved with the baby. Arizona proposes to Callie, but doesn't get an answer before Callie is thrown through the windshield of their vehicle in an accident. She is severely injured and has to deliver her daughter early but both pull through.
Derek is worried that Meredith is going to get Alzheimer's, so he starts working on a clinical trial with Meredith to cure Alzheimer's. Meredith helps work on the trial, but when Richard's wife gets on the trial, Meredith checks the drugs to make sure that Adele's is active and not placebo. This effectively gets the trial shut down and creates a rift in Meredith and Derek's marriage.
There is a race among the residents for next year's Chief Resident. Owen is put in charge of picking who will win the spot, so Cristina wants him to stop thinking about her as his wife until he's made a decision. Alex brings some of the children that Arizona worked with in Africa to Seattle for surgery. Alex and Meredith appear to be the two favorites for Chief Resident, but he tells Owen about what Meredith did in the clinical trial and puts both of them out of the running.
Teddy meets Henry, a patient who has a severe medical condition that whose insurance has run out. Teddy agrees to marry him because she has great medical insurance, and eventually the two of them fall for one another.
One of the kids that comes with Alex's group is Zola, a six month old with spinal bifida. Derek takes a liking to her and they decide to adopt her. The season ends with Meredith bringing Zola home on her own to an empty house because Derek is mad about the clinical trial and Cristina announcing that she is going to get an abortion because she doesn't want a baby.
Meredith and Derek parent Zola separately, which raises some major red flags for the adoption counselor. After finding out that Meredith has lost her job due to the trial and that Derek moved out she says that they will have to reevaluate the placement and take Zola away while that happens. They fix their romantic relationship and eventually get Zola back.
Meredith gets her job back because Richard takes responsibility for Meredith's actions with the trial. He gives up being the Chief of Surgery and gives the job to Owen. Derek refuses to work with Meredith anymore, so she switches her specialty to general surgery.
Richard puts Adele in a home as her Alzheimer's is too advanced for him to handle. Richard starts dating Catherine Avery, Jackson's mother. This gives Meredith and Jackson something in common.
Jackson and Lexie break up because Lexie still loves Mark. Cristina and Owen start fighting about Cristina having an abortion, and Owen cheats on Cristina. Teddy's husband, Henry, dies while Cristina operates on him and Owen waits hours while Teddy finishes a surgery before telling her. Teddy gets mad at Owen and grieves. Teddy gets offered her dream job but doesn't want to leave Owen when his marriage is falling apart. He fires her so that she will have to take the job.
The fifth year residents all have to take oral board exams to finish their residency. The night before the exam Meredith comes down with the flu and April gives her virginity to Jackson. April doesn't pass her boards, and the doctors that do pass all make plans to go to different hospitals.
Bailey gets engaged to Ben, but he decides he wants to quit being an anesthesiologist and gets accepted to the residency program at UCLA. They have to make their relationship work long distance.
The season ends with Arizona, Mark, Lexie, Meredith, Derek, and Cristina going to Boisie to help with the separation of conjoined twins, but their plane crashes. Derek's hand is shredded, the pilot is paralyzed, Arizona has an open femur fracture, Mark has a cardiotampano
The season begins about a month after the plane crash. Cristina has gone to Minnesota to escape the aftermath of the crash, Meredith is an attending general surgeon at Seattle Grace Mercy West, Derek is trying to get his hand back to being able to operate, Mark is on life support until he is taken off and dies, and Arizona has an infection in her leg which has to be amputated to save her life.
Alex feels guilty about Arizona's leg, as he was supposed to be on the plane but she took his spot because he was going to leave Seattle. He also was the one to cut off her leg. Arizona and Callie's relationship suffers because Callie wasn't able to save the leg and Arizona blames her for letting it be cut off. She also suffers from phantom limb pain.
Cristina returns to Seattle after her mentor in Minnesota dies. Owen asks Cristina for a divorce now that she's back, because he knows they will never truly want the same things in life. Alex buys Meredith's mother's house from Meredith now that she and Derek are completely moved into the Dream House.
Jackson and April continue to sleep together after April comes back to Seattle, but after having a pregnancy scare they stop having sex. Jackson has trouble adjusting to the fact that Richard is dating his mother, Catherine Avery.
Meredith finds out that she's pregnant and that the baby is a boy. She's worried that she will have another miscarriage, so she doesn't want to tell anyone except Derek until the end of her first trimester.
Bailey and Ben get married, but their wedding is delayed when Richard's wife, Adele, is brought into the ER. He sends Bailey back to the wedding to get married after the surgery but Adele dies anyways. Because of the wedding, Alex and Jo hook up, as do Stephanie and Jackson, starting two new intern-attending relationships. April starts dating a paramedic named Matthew and they later get engaged. Jackson almost dies in an explosion and April says that she won't get married if he tells her not to. He tells her that she should get married.
The doctors decided not to settle with the airline, because they feel that if they did settle there could be another crash for somebody else. The hospital and Owen are found negligent because the airline had a history of mechanical problems. Callie is Mark's proxy after he dies, and she along with Arizona, Meredith, Derek, and Cristina are awarded fifteen million dollars each. The insurance company finds a loophole, meaning that they won't pay the settlement and the hospital will have to pay. This means the hospital faces bankruptcy and will probably have to close. There are many new rules and the ER closes down. Callie and Richard go to another hospital run by the prospective buyer and it's run in an impersonal way entirely by procedure. The doctors from the plane crash decide to buy the hospital along with the Harper Avery Foundation run by Jackson's mother. The new hospital board is then Jackson, Meredith, Derek, Cristina, Callie, and Arizona.
There is chaos in the hospital as none of the board have experience running the hospital besides Derek. Many of the hospital staff quit because of the instability and uncertainty surrounding the hospital. The new protocols put in place when the hospital was going to be franchised cause confusion for the doctors. They decide to rename the hospital Grey Sloan Memorial after Mark and Lexie.
Meredith and Derek have Bailey run Meredith and Zola's DNA in her genome sequencer to find out more about Zola and see if Meredith inherited the genetic markers for Alzheimer's from Ellis. Meredith's results come back positive for multiple markers.
Some of Bailey's patients end up with serious post-op infection. She finds out that they have staph infection and that she is a carrier of a strain of staph. She thinks she may have done something wrong and that is what gave it to her patients.
Arizona cheats on Callie with a visiting doctor.
Meredith falls down the stairs, but her baby seems fine. That night a storm hits Seattle and she goes into labor. The power in the hospital goes out from the storm and Meredith ends up needing an emergency C-section in the dark. Meredith is awake during her surgery as the interns close her up, she realizes that she has internal bleeding from her fall on the stairs.
The season ends with Bailey saving Meredith's life and Richard being electrocuted by water in the hospital basement.
Heather goes down to look for Richard, but when she tries to help him, she is also electrocuted and hits her head. She later dies in surgery. Her death opens up a spot for Bailey's husband Ben in the intern program.
Callie and Arizona separate and Callie moves in with Meredith and Derek temporarily. Meredith and Derek are glad she's there as they struggle to cope with having a newborn and a toddler and being surgeons. Arizona starts having an affair with Leah Murphy, but breaks it off when Callie tells Arizona that everyone makes mistakes.
Richard slowly recovers from his injuries. Meredith is his medical proxy, but she is confused because he never asked her. She feels conflicted because she doesn't want to admit that Richard is like a father to her. This also causes problems between Meredith and Catherine because Catherine thinks she should be the one making calls about Richard's care.
April and Matthew's relationship is rocky because April still has feelings for Jackson. At April's wedding Jackson stands up and confesses his love for April. The two run away from the wedding together and secretly get married. Later April and Jackson find out that they are having a baby.
Meredith wants to continue her mother's research and Derek promises that he will make it so that she can put her time into that and he will take care of things at home. But Derek and Callie start working on brain mapping, which starts to take up all of Derek's time. The President and the USA government buys his work, meaning he has to back out of his research with Callie. Derek wants to move to Washington, but Meredith decides to stay in Seattle.
Bailey develops OCD behaviors, which puts her career in jeopardy. The source of the behaviors seems to be the infection she accidentally spread in season nine. Alex's father shows up at the hospital as a junkie and eventually dies.
The hospital orders a no fraternization policy after Leah complains about Callie's reaction to her relationship with Arizona. Relationships between the doctors is discouraged and relationships between subordinates and superiors is forbidden without an HR issued contract.
Derek's sister Amelia comes to Seattle and decides that she wants to stay. She takes over nost of Derek's surgeries in Seattle. Arizona is offered a fetal surgery fellowship. Dr. Maggie Pierce comes from Boston to be the new Head of Cardio. Alex leaves the hospital to pursue a private practice.
Meredith and Cristina have some serious rough patches in their relationship. They fight over Meredith's new 3-D printer that Cristina needs to perform an experimental procedure. Cristina's procedure turns into a clinical trial that gets her nominated for a Harper Avery Award. Because the hospital is partially owned by the Harper Avery foundation the doctors find out that they will never be able to win a Harper Avery. Cristina goes to Zurich, Switzerland where her ex-fiance Preston Burke, tells her he's looking for someone to run his hospital and offers her the job. Cristina decides to take the job and Shane decides to go with her.
The season ends with Meredith telling Derek she doesn't want to move to DC and Cristina and Ross going to Zurich.
Meredith finds out that Maggie is her half-sister and that Maggie is Richard's father. Maggie and Richard struggle to have a relationship. Meredith doesn't want to let Maggie into her life because of what happened to Lexie.
Arizona decides to take the fetal surgery fellowship. She finds out her mentor has a brain tumor and only has six months left to live. She has to teach Arizona everything she knows before she runs out of time. Cristina left her seat on the Board to Alex, which gets him fired from the practice. The Board decides to give his seat to Bailey, and make Alex the peds attending to replace Arizona. Amelia becomes the new Head of Neuro which annoys Derek once he decides to stay in Seattle with Meredith.
Callie and Arizona decide to officially end their relationship. Jackson and April find out their baby has a fatal condition and he dies shortly after giving birth. April decides she needs a fresh start and joins Owen on a military tour. Catherine and Richard get married. Maggie finds out that her parents have only been together because she was around for years and are now getting a divorce.
Derek decides to change his mind and go to Washington. The time apart helps his relationship with Meredith and he decides again to come back to Seattle for good. On his way home, Derek stops to help out with a car accident that he narrowly avoids. As he gets back into his car and pulls onto the road he is hit by a semi truck. He dies in the hospital after the doctors there aren't prepared to handle a trauma and Meredith takes him off life support. Meredith leaves with Bailey and Zola in the middle of the night after Derek's funeral. She later finds out that she and Derek conceived a child before he died and gives birth to Ellis Shepherd.
The season ends with Owen deciding to give up the position of Chief. The Board will have to decide on a new Chief of Surgery. Jackson tell April that if she goes back to Jordan that he won't be able to be her husband when she comes back.
Meredith, Maggie, and Amelia live together in Meredith's mother's house and Meredith struggles to adjust. Arizona starts looking for a roommate. Alex and Jo move into a loft and Jo rejects Alex's marriage proposal. Meredith starts to teach an anatomy class.
Bailey fights to become the Chief of Surgery and eventually gets the job. This causes problems when Ben performs several dangerous surgeries. Bailey has to be talked out of firing Ben and struggles with not giving him special treatment. They decide that they need to separate their work lives from their home lives.
Callie's new love interest, Penny Blake, ends up being one of the residents that worked on Derek before he died. When she comes to Grey Sloan Memorial Meredith and Amelia find it difficult to teach her because of her connection with Derek's death.
April comes back from Jordan and Jackson still wants a divorce. She finds out that she's pregnant with another baby but gets the divorce anyway because she doesn't want that to be the only reason Jackson stays with her. They initially have a lot of problems, but eventually decide to co-parent peacefully.
Bailey hires a new cardio surgeon to work with Maggie, but he turns out to be the fiance of Owen's sister that cheated on her right before she went missing in action in Syria. Meredith and Riggs are attracted to each other but Meredith isn't ready to date again after Derek.
Meredith gets attacked by a patient and has a hard time recovering. Her injuries give her time to make up with Amelia. Amelia gets herself sober again. Her relationship with Owen develops and she decides to propose.
Penny wins a grant and has to live in New York for at least a year. Callie decides that she wants to go and take Sofia with her, without asking Arizona. Arizona thinks Callie will take Sofia away from her and they end up going to court for full custody of their daughter. Arizona wins and Callie is devastated.
The season ends with Arizona giving Callie permission to take Sofia to New York with her and Penny. Meredith convinces Derek and Amelia's family to come to the wedding, Ben gives April a C-section on Meredith's dining room table, and Alex thinks Jo is cheating on him and beats up DeLuca.
DeLuca decides that he wants to press charges against Alex for beating him. Bailey has to decide how to handle her personal feelings for Alex and what she has to do, as does Meredith. Alex ends up moving in with Meredith and Maggie and working in the clinic until he finds out if he's going to jail or not. Meredith and Riggs try to hide their attraction for one another because Meredith doesn't want to hurt Maggie's feelings.
Owen and Amelia decide to have a baby. Amelia thinks that she's pregnant, but when she finds out that she's not it reminds her of how on Private Practice she gave birth to a baby who died less than an hour after his birth. She leaves and lives with Stephanie for a while before moving back in with Meredith.
Leah Murphy returns to work with Maggie. She went to another hospital after being fired from Seattle and once she got better she came back. Leah's return along with Alex's trial causes Catherine to go to Bailey and ask her to reevaluate the residency program.
Eliza Minnick comes into the hospital, which offends Richard. The attendings side with Richard out of loyalty, while the residents love Eliza's technique. Both Richard and Eliza realize that the other is right about certain things.
Arizona develops feelings towards Eliza and also struggles with Alex and DeLuca's situation because DeLuca is her roommate and she trained Alex to be the surgeon that he is. Jo confesses to Alex that she turned down his proposal because she is already married. She is afraid to get a divorce because her husband is abusive and she doesn't want him to find out who or where she is now. Alex decides to take the plea deal and go to jail without a trial so Jo won't have to testify, but DeLuca decides to drop the charges because he has feelings for Jo.
Maggie's mother has an aggressive form of breast cancer. She makes Jackson promise not to tell Maggie but eventually he says he won't operate on her unless she tells her. Maggie does everything that she can to save her mother, but she eventually dies.
Season Thirteen is still ongoing.