The film is loosely based on W.W. Jacobs' short story The Monkey's Paw.

Ryan and Clare discuss the idea of the multiverse early in the film. The appearance of Jerry O'Connell's unnamed character later in the story implies that perhaps this takes place in the universe of Sliders, where O'Connell plays a character who can travel through different dimensions of the multiverse.

When Clare, June, and Meredith take a selfie during the scavenger hunt, an elevator can be seen directly over Meredith's head, foreshadowing her death.