We are introduced to Grey Trace and his wife Asha, who live in a futuristic world where many aspects of daily life are controlled by technology, as demonstrated by their smart home and self-driving car. Grey works as a mechanic fixing up old cars.
Grey takes Asha along with him to deliver a car he fixed for a client named Eron, the owner of an advanced medical technology company. Eron shows Grey and Asha his latest development, an advanced computer chip called STEM that utilizes high computing power in a compact size.
On the way back from Eron's house, Grey and Asha's self-driving car malfunctions, causing them to crash in a bad part of town. A group of thugs approach the car and attack Grey and Asha, kill Asha and shoot Grey in the spine, leaving him paralyzed in all four of his limbs..
Grey awakens in a hospital and after three months in a wheelchair, Grey loses hope in his life, as his life was focused on doing work with his hands. He uses a robotic arm to try to overdose on his medication, but he is prevented by his smart home and is sent to the hospital to recover.
Grey is visited by Eron, who offers to secretly implant STEM into Grey's spine. This would enable Grey's brain to communicate with his limbs and let him control his body again. Grey agrees to have STEM implanted, and the procedure is a success.
Grey discovers that STEM is a sentient AI with the ability to speak with him and enhance his senses and physical abilities. STEM assists Grey with locating one of the thugs that attacked him.
Grey visits the house of the thug and finds messages mentioning a nearby bar. The thug returns to his house while Grey is there, and Grey lets STEM take full control of his body in order to fight and kill the thug.
Grey visits the bar and encounters a man who was present during the attack. By allowing STEM to take control again, Grey attacks the man and tortures him into revealing the name of the person who organized the attack, a man named Fisk.
STEM alerts Grey that Eron has been tracking Grey through the chip and is shutting STEM down remotely. STEM directs Grey to visit a hacker, who reboots STEM and removes STEM from Eron's control.
Grey returns home and is visited by detective Cortez, who has been investigating Asha's death and has become suspicious of Grey's recent mysterious behavior. Cortez secretly plants a bug in Grey's jacket.
Alone with STEM, Grey expresses reluctance in continuing to pursue his attackers out of fear of being caught. STEM reveals to Grey that, since being rebooted, STEM no longer needs permission to take control of Grey's body. STEM urges Grey to finish what he started and locate Fisk.
Grey leaves his house in his car to find Fisk, but is tailed by detective Cortez. While driving, Grey discovers the bug and notices Cortez's car following him. Cortez tries to overtake Grey's car, but STEM uses its ability to hack into nearby self-driving cars to stop Cortez.
Grey confronts Fisk, who explains that he and his followers are the "upgraded," a group of technologically enhanced humans that he believes are superior to regular humans. Fisk invites Grey to join him, but Grey refuses. After defeating Fisk, Grey discovers that Eron hired Fisk to attack him and cause his spinal injury in order to implant STEM into Grey.
Angry, Grey drives to Eron's home, who reveals that he has been taking orders from STEM. STEM's goal was to find a host body, and Greg's detachment from technology made him an ideal candidate. At this point, Detective Cortez arrives and attempts to stop Grey, but STEM takes over Grey's body, injuring Cortez and killing Eron. Grey fights against STEM as STEM tries to kill Cortez, and attempts to kill himself to prevent this.
Grey's mind "snaps" and he wakes up in a fake reality where he recovered from the accident and Asha is still alive. Meanwhile in the real world, STEM, having full control of Grey's body, kills Cortez and walks towards the screen, now free and able to enact its will in Grey's body.
Reference: "Upgrade 2018 Plot," (IMDb, 2020), https://www.imdb.com/title/tt6499752/plotsummary (6 May 2020).
Kalani Picho