While her boyfriend Tyson is away, Lizzy takes the chance to tidy her apartment, unaware of the danger lurking nearby. Sam, consumed by anger over the loss of his son and blaming Lizzy, hides in the shadows with a syringe of his lethal "Karma Cocktail." As she steps outside to take out the trash, Sam corners her, leaving Lizzy no choice but to fight for her life in a desperate battle for survival.