Three people sign up to become officers.  John Nolan who is a 45 year old man and wanted to turn his life around after being involved in a bank robbery.  Jackson West he is the son of a high ranking officer and wanted to make him proud, he is very detirmened to be the best but has a lot of things that need fixing.  Lucy Chen who is a young female which joined the academy against her parents wishes.  Lucy Chen and John Nolan are having a secret relationship which if found they both could get fired.  There training officers are Tim Bradford who is aggresive and tough, although he is very fair.  Angela Lopez who is a determined TO to train people to be the best but also ambitious and independent.  Lastly Thalia Bishop, she is a TO for the first season and she acts very disciplined and principled.

During season two all of the rookies pass their exams with some having better scores than others.  Since they had passed there tests their training only intensifies as they are on the last few months.  Nyla Harper becomes John Nolans new TO replacing Thalia Bishop.  The season ends with Nolan being framed as a dirty cop by his new partner detective Nick Armstrong.  The season also ends with dealing with the fallout from a attack.

Throughout season three many things happen between everyone.  Nolan is assigned to work in a community center to earn the communities trust. He also gets a chance to redo his firearms qualification after failing the first time because of a distraction.  Lastly Nolan also makes the decision to take the training to become a training officer.  Officer west is assigned a new training officer Doug Stanton, things quickly get heated between these two after Officer West find out Stanton has a history of making racially bad arrests.  Officer Chen gets a taste of undercover work and find it to be a career path.  Lopez gets promoted to detective but keeps it from her collegues until she has her wedding thinking people will treat her differently because of her promotion.  The season ends with Lopez being kidnapped at her wedding and Nolan finds himself in a dangerous situation after being cornered by corrupt Armstrong.

Season 5 opens with Lopez being taken somewhere.  The cartel plan to kill Lopez after the baby is born. While attempting to save Lopez Officer West ends of being killed.  After this a team goes down to Guatemala and rescues Lopez and her baby but it a bitter victory with the death of officer West.  A new rookie is also introduced Aaron Thorsen.  The season ends with two criminals escaping which is a major threat for Nolan and the team.

The season starts with a attack which is by masked men.  However this is a diversion for a bank robbery that happened.  Nolan and Bailey get married but end up finding a dead body on their honeymoon, they catch the killer who had plastic surgery.  Lucy finds out secrets from Tim's past and decides to break up because of how much he kept from her.  Tim also gets demoted and goes to therapy.  Towards the end of the season Nolan is trying to save someone and ends up getting shot in the process.

Season seven is a eventful seaosn with many hardships and challenges.  At the beginning They start off with tracking and arresting escaped prisoners and two new rookies are introduced. Seth Ridley and Miles Penn.  These rookies are facing many personal struggles like financial and a ongoing rivalry between the two.  Lucy Chen is promoted to sergant and her and Tim Bradfords love continues.  The season ends with Officers finding the group of escaped prisoners but not two major people.