An abandoned research project on invisibility returns to haunt Eureka. Carter and Zoé become tangled in a web of strange occurrences that lead to Carter’s disappearance and the possibility that he might never reappear.

Sheriff Jack Carter becomes absolutely irresistible to every woman in Eureka. But if he doesn't get his mojo under control, they might just eat him alive.

Beverly Barlow returns to town just as a parasitic bacterium threatens to destroy Eureka, by turning everything to gold and then into rust --- people included.