Liz Cook is a cop who was on the call (along with partner Dennis Baldwin) when Amy Kettering's young daughter, Emily, is kidnapped. Her abduction was part of a conspiracy to force Amy to kill Ed Borden, a reporter looking to expose a group who had stolen a flu vaccine and planned to sell it on the black market; if Amy didn’t comply, Emily would die.
While following a suspect, Liz falsely informed Amy that Dennis Baldwin was part of the plot, and took Baldwin's gun while holding him at gunpoint. She also removed Amy's cuffs and gave her a gun of her own, which Amy pointed at Baldwin while demanding to know Emily's whereabouts. At that moment, however, Liz turned heel and shot Baldwin to death, revealing herself as a villainess.
Liz's plan was to frame Amy for Baldwin's murder, and she chased after the protagonist, intent on killing her. She later returned to Amy's home and grilled her mother regarding her daughter’s whereabouts. Later on, the evil Liz was seen in the cellar of the home of politician Paula Stronin, who was revealed to be the true mastermind behind the theft of the flu vaccine; her motive for orchestrating the conspiracy was to become rich. After killing co-conspirator Duncan Hall (the film’s tertiary villain), Amy battled Liz once again, with said battle ending when the villainess was handcuffed to her own car and forced to reveal Emily's whereabouts: the car’s trunk. Though not shown, Liz was arrested for her role in the conspiracy.
- Sonja Bennett also played serial robber Beth on Tru Calling, and later played crazed villainess Chelsea Richmond on Motive.