|“||I made him promise.||”|
Born in Santa Monica, California, Kristin was present when her parents, Joe and Sylvia, were murdered by a serial killer (later identified as Billy Flynn), who broke into their house. She was placed in a closet alongside her older brother Matt. Since she was an infant at the time, she never remembered the incident. Following the murders, Kristin and Matt were placed under the care of their grandparents, who told them their parents died in a car accident. She grew up to have a normal life and eventually came to be the caretaker of Matt's daughter and her niece Ellie whenever Matt was occupied with his work as an LAPD detective.
Our Darkest Hour (Part 1)
While Matt was away at work, Kristin stayed at Ellie's house. The two are abducted by Billy and he brutally pistol-whipped and raped her in front of Ellie. He then takes them to Kristin's parents' house, where he kills the current resident and ties Kristin and Ellie up in the bedroom with duct tape. Morgan, tracking Billy down with Matt, is able to figure out their whereabouts and they drive there. Searching the house, Morgan finds Kristin and Ellie but is ambushed by Billy and tied up by a coerced Ellie. Matt enters the room soon afterward is forced to get on his knees by Billy, who psychologically tortures him by holding Ellie hostage. When Matt tries to make a relenting Morgan promise him he will take care of Ellie, Kristin forces Morgan to make the promise. Morgan does so, and Billy shoots Matt at point-blank range in the chest, killing him. He then takes Ellie with him and leaves her alongside Morgan for death as she and Ellie scream.
The Longest Night (Part 2)
Sometime after Billy left, Kristin is taken to the hospital by an ambulance. Prentiss accompanies her, to which Kristin is able to inform her that Billy was always listening to the radio while he drove Ellie and her to the house. She then tells her about her forcing Morgan to make the promise. Prentiss later gets a call from the hospital, announcing that Kristin's lungs collapsed from the wounds inflicted by Billy and she died.