Catherine and Vincent track a mysterious beast while keeping their individual agendas from one another in a clever game of cat-and-mouse. Meanwhile, Heather has a bombshell revelation for Cat, and Tess confronts Gabe about his real motives for helping Cat.

Cat gets a blast from the past as she attends her high school reunion, where she uncovers more of her past than she ever anticipated. Meanwhile, Vincent meets up with one of his old military buddies who is hiding a very dangerous secret.