As an experiment that will recreate the first moment of the origins of the universe, the Big Bang, goes terribly awry, the town’s geniuses turn into morons, leaving the fate of Eureka in the hand of Jack Carter and an antisocial young ubergenius.

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.

Eureka's annual dog show is underway and is like none other. Meanwhile, Sheriff Carter experiences an earthquake; Zoe debates quitting the accelerated physics program; and Allison starts the process of fitting her wedding dress.

Carter interviews for a job with the Department of Homeland Security, after being terminated as the sheriff. Deputy Lupo decides to resign after discovering that a very personable robot is the new sheriff.

Eureka's teenagers who appear to have been manipulated while asleep, gathered in a field where they assembled a strange structure comprised of scrap metal and electronics.

When the 5 get back to their time, things are changed everywhere. As the Henry tries to fix the machine that transported them in the first place, Dr. Grant is making himself comfortable as he can. Jack is still trying to wrap his mind at the fact that he asked Tess something that she says yes to and the fact that the group's positions changed. As one thing leads to another, a twist happens and things get a little dicey.

Zane pesters Jo for details she does not want to reveal. Carter problem-solves at Andy and S.A.R.A.H.'s wedding. Elsewhere, Zane's actions make him and Fargo unexpectedly airborne.

When an explosion in the Astraeus lab accidentally sends Andy to Titan the team must devise a plan to save him before it's too late! Eureka

The town huddles in a last attempt to locate the vanished Astraeus before it's too late!

Eureka is cut off from the world by a malfunctioning experiment that threatens to eradicate the town's populace.

Wormholes randomly materialize around Eureka as the Department of Defense is set to shut the town.