As Eva Thorne prepares to seal off the subterranean military complex, Zoe's life is endangered as her body begins to rapidly age.
The town's mayoral race is disrupted when Zoe's science partner inadvertently causes a second sun to appear over Eureka.
A mysterious "superhero" who can walk through walls is causing a ruckus in Eureka. Meanwhile, Zoe and her friends become stranded with Zane Donovan in an abandoned subterranean facility.
When an Egyptian tomb is opened at Global Dynamics, strange things start to happen, leading Fargo to believe it is the mummy's curse. The mummy, however, has disappeared, and Carter investigates.
On Allison and Stark's wedding day, Sheriff Carter finds himself stuck in a time loop, causing him to experience the same lousy day over and over again. Meanwhile, Sheriff Carter's sister Lexi visits Eureka.
The town's annual dog show gets into full swing—complete with exploding robotic canines. Meanwhile, Sheriff Carter experiences an isolated earthquake, Zoe contemplates quitting the accelerated physics program, and Allison starts fitting her wedding dress.
Sheriff Carter and Allison investigate the disappearance of a scientist from a sealed biosphere. Meanwhile, "The Fixer" attempts to make Eureka's ventures more profitable.
Pamela becomes increasingly concerned when her stalker crosses the line by talking to her children. Roxy and Roland exchange words after Roland acts once he learns of Trevor's addiction. With Jeremy leaving for the first time Denise and Frank share an emotional goodbye. The Holden's get a visit from an ...
Claudia's dad Randall drops by. Joan who is worried about being a new mom, has a baby shower coming up. Pamela may need help to deal with a fan that goes to far.
Claudia is shocked when her mom drops by. Roxy gets cold feet before taking the test for her GED. A young man gets help on dealing with the loss of his dad.