Dr. Whiticus creates an incredible "weather machine" intended to reverse the effects of global warming which instead stirs unexpected results.

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.

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.

It's Allison and Stark's wedding day and Carter finds himself reliving it over and over. Meanwhile, Carter's sister, Lexi, visits the town.

Trust issues are produced by a scientific find, along with sinister results. Zoe's life is in jeopardy, and Eva Thorne knows what has caused the predicament.

Dr. Tess Fontana reopens Section 5, causing objects to become ambulatory , possibly due to poltergeists.

Allison's baby shower fetches her a load of eco-friendly gifts and the discovery of a drowned scientist in a location where drowning is impossible.