Delia first appears at the opening of the film, when she and a guy are in the backseat of a parked car making out, a police officer knocks on their window and asks Delia if she is being forced against her will to do anything. She confirms to the officer that she is not, and the officer tells them to say warm before leaving. Delia strips out of her top revealing a pink bra and panties. She continues to make out with the guy. Then her tentacles come out of her stomach and they begin to mate. The guy ultimately dies before she can complete her task.
Later, Delia and another alien Jasmine (Lindsay Maxwell) report back to their leader, Constance Snowden (Kim Poirier). Constance tells them not to be sloppy, and be more careful. We learn that the Decoys are aliens who are attempting to ensure the continuation of their species by mating with males. They must do this in a cold environment or the process won't work.
Delia then seduces Henry Robbins (Reamonn Joshee) outside a hospital. She strips out of her clothes revealing a leopard bodysuit. The two end up lying down in the snow and begin mating. However, the guy gets frightened and runs off before she can copulate with him.
Next we see Delia seducing another boy inside the library. They end up going inside to the stands at the football field. Delia was wearing thigh high stockings in a pleated mini-skirt, and began stripping out of her blouse revealing her pink bra. However, an overhead heater suddenly kicked in and began bothering Delia. She was forced to abandon the seduction and attempted mating. We see her fleeing across the football field in the snow as the guy was left stunned.Delia then goes to a dance and seductively dances with many of the guys. This prompts Stephanie Baxter (Kailin See) to recognize that she is a Decoy. Delia runs off after alerting Angeline (Natalie McFetridge).
Stephanie and Henry then track her and her fellow Decoys down and fight with Delia. Delia is wearing thigh high stockings in this last scene where she begins to attack Sam Compton (Tyler Johnston). Delia turns into an alien and they burn her to death.