When Elaine was a child, she was taken to a psychiatric ward called the Salvia Unit to go undergo electroconvulsive therapy after witnessing her father kill her mother. Isaac Taylor and Jonas Borner were her doctors there. One night, the police station got an emergency call from the ward, so a young Gabriel went to investigate. There, he found a male employee sexually abusing Elaine. Gabriel attacked the man, ultimately killing him.
In the present day, Elaine has taken Taylor captive. Around this same time is when Gabriel unearths the memory card at the grave of Steven Mills’ mother. He enlists a colleague to retrieve whatever’s on it and then tells Elaine about this discovery. Elaine panics, takes the memory card from the colleague, and drives off with it. Once Gabriel discovers she has it, he chases after her in his own car. This chase ends in them both crashing, though Elaine’s able to escape before Gabriel can catch her.
Back at the station, Gabriel finally watches the video on the memory card and spots Elaine in the footage. He goes to her house to search her things and finds a photo of her as a child. He recognizes her face and suddenly understands that she’s the killer and targeting people associated with the Salvia Unit.
By the time Gabriel gets to Taylor’s office, Taylor has bled to death. While Gabriel is there, Elaine picks up Hannah from school. Soon after getting in the car, Hannah realizes something is off and protests. Elaine slams on the brakes, removes Hannah from the passenger seat, and stuffs her in the trunk. While Hannah’s in the trunk, Elaine talks to Gabriel on the phone and tells him to meet her at an undisclosed place.
Gabriel figures out that the place is the now-abandoned Salvia Unit. He meets Elaine there, and the two have a confrontation that ends with Elaine pouring gas on Gabriel and herself and setting fire to the place. Instead of letting them both burn to death, Gabriel picks Elaine up and walks out of the building, both of them engulfed in flames.
Gabriel is badly burned, but he survives. He’s covered in bandages in a hospital room as Lisa and Hannah, who Elaine dropped off before meeting Gabriel at the Salvia Unit, watch over him.