When mites threaten to take down Global Dynamics, Jack is called into action since Jo is in the middle of training. Allison is struggling with the fact that everyone things that her brain doesn't work and she is determined to prove that she is back in action again. 

The Eureka atmosphere becomes toxic when Department of Defense auditor comes to assess the team's relationships.

The Astraeus candidates go through their final interviews while Carter and Allison appeal their relationship audit.

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

In the season finale - It's chaos in Eureka when an energy beam rips through main street but the Astraeus launch must go on...with or without Eureka intact.

The Astraeus crew returns to Eureka four years later and must adapt to a myriad of changes, including a more oppressive version of Deputy Andy.

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

Henry conducts a preparedness drill that winds up a disaster and Fargo faces a hard reality.

Fargo is convinced that Holly is still inside of the Matrix computer, but the DOD is determined to wipe its hard drive clean -- losing Dr. Marten forever.

Carter's romantic surprise for Allison turns deadly when they're trapped in a sinking marine lab with time and oxygen quickly running out.

When Allison's genius older brother comes to meet her new husband, Carter feels the pressure of not being smart enough to measure up.

Jack and Allison's perfect honeymoon is interrupted when sabotage is discovered in Eureka. Elsewhere, Holly faces another hurdle to remain intact.

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

The people of Eureka are being kidnapped and replaced by body-doubles one by one unless Allison, Fargo and Zane can figure out how to avoid capture and save their town.

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