Driving with his headlights off along a tranquil country highway, Chris Pratt is eager to show his girlfriend, Kelly, and another couple the mesmerizing swarms of fireflies that light up the summer night. Unfortunately, a tragic accident occurs when he collides with a combine that is stalled on the road. While both Chris and Kelly survive, the other passengers do not make it. As a result of the crash, Chris suffers significant injuries, including brain damage that impairs his short-term memory—a condition similar to anterograde amnesia—as well as issues with anger management.
Fast forward four years, and Chris is focused on rebuilding his life. He attends classes designed to help him learn new skills, grappling with everyday tasks that challenge his memory. To assist him, he keeps notes in a small notebook as a survival tool. Although he is emotionally supported by his roommate, a blind man named Lewis, his wealthy family only provides him financial assistance. He works late nights in a small-town bank, where he dreams of training as a teller—an ambition that is met with disdain by Mr. Tuttle, the bank manager. His reality becomes even more complicated when he draws the attention of a gang plotting to rob the bank. The gang’s leader, Gary, is a figure from Chris's past who once envied Chris’s popularity and wealth as a hockey star. Under the guise of friendship, Gary seeks to exploit Chris’s vulnerability, using a young woman named Luvlee to lure him in.
As Chris navigates the bullying taunts from the gang about his condition and capabilities, tensions grow between him and his supportive friends, Lewis and Ted. On the night of the robbery, Chris attempts to withdraw from the scheme but is coerced into emptying the vault at gunpoint. When his friend Ted, the sheriff's deputy, unwittingly interrupts the robbery with doughnuts, chaos ensues, resulting in a violent shootout that claims the lives of Ted and two gang members, Marty and Cork. Amidst the fray, Chris seizes the opportunity to escape with the stolen money, prompting a compulsive return to the site of his near-fatal accident, where he buries the cash by the roadside.
As events unravel, Gary is gravely injured, and the remaining robber, Bone, along with Gary, force Chris to retrieve the money buried in the snow. Realizing the urgency of the situation, Chris utilizes the sequencing skills he learned in therapy to devise a plan for survival and the rescue of his friend. Yet, he fails to maintain his guard and is caught by the robbers at their arranged meeting place. In a tense moment, as Chris digs for the buried cash, he witnesses Gary's condition rapidly decline. To protect Lewis, Chris cleverly uses a shotgun hidden in one of the bags he has prepared and manages to kill Bone just in time.
After this harrowing ordeal, Chris returns the money and turns himself in. However, the FBI investigation clears him of wrongdoing due to his medical condition and the incriminating video evidence captured during the robbery. In the aftermath of the events, Chris reconciles with Lewis, and they embark on a new venture by opening a restaurant with a loan from the bank. Despite the traumatic experiences he has endured, Chris holds onto hope that one day he will find the strength to face Kelly and seek her forgiveness for the loss she endured as a result of the accident.
