This show depicts that. While celebrating the anniversary of the town's founding, Sheriff Carter, Deputy Lupo, Drs. Blake, Deacon and Fargo inadvertently travel to the year 1947. Carter, Lupo and Fargo are arrested by the military suspected as spies, whilst Blake and Deacon fit in as a nurse and mechanic respectively.

While Deacon is finding a way to reset the timeline, Allison discovers that Fargo is now the director of Global Dynamics, and she is now the medical director. Andy replaces Lupo as deputy, while she finds herself the head of security of GD; Andy realizes that Carter and the others changed the timeline.

Carter is uncomfortable with Tess moving in with him. Meanwhile, Fargo has trouble coping with being director of Global Dynamics. After witnessing a malfunctioning demonstration in the non-lethal weapons lab, everybody inside Global Dynamics start showing signs of rage before they are no longer lucid.

Space Week begins normally enough, with everyone caught up in a rocket race to the moon and back. But when the town somehow becomes over-oxygenated, the returning rockets could blow up Eureka. Allison deals with a major problem during Eureka's space week festival. Tess and Carter broke up, this week I was pleasantly surprised to see Jo and Zane making some tiny steps forward.

This is a crossover episode with Warehouse 13. Claudia Donovan is invited to Eureka, where she hopes to find all the coolest new technology. But instead of new technology, she finds that objects are randomly teleporting into the town, apparently from 1947. It is revealed Dr. Grant is the cause, acting like a magnet to the past.

All the AI in town begins to behave strangely as Sheriff Carter, Fargo, Dr. Grant, and Kevin go on a camping trip. They are soon attacked by a rogue Titan rover unit which has developed parental feelings over Kevin's school project, a tiny emotional robot. Meanwhile, Henry reveals to Grace about his time travel, and has her restart their relationship from the beginning.

Zoe returns for a visit but the fun is cut short when people start to turn into stone. Meanwhile, the truth about Dr. Grant's past is put into jeopardy when the identity Fargo constructed for him draws attention. I thought that they were going to stall in first gear and keep the we should just be friends standoff going a bit longer.

The gang begins seeing visions of people from their pasts, while the town seems to be collapsing around them. Meanwhile, Dr. Grant gets involved with a mysterious faction. For the rest of the team, it was a unique experience seeing each deal with their fears. Fargos fear being represented by a ten year old Jessica Lansky was entertaining to say the least.

Beverly and the Consortium, using the powercell from the stolen DED device to power their own Bridge Device, seek to return Dr. Grant to 1947. But when Carter intrudes, events are set in motion which trap both men in the past and threaten to alter present-day Eureka once again, while the powersurge has dire consequences for Allison.

Taggart's "Santaology" technology is tampered with, threatening to shrink the entire town out of existence. Carter can't get into the Christmas spirit especially with the town surrounded by a force-field. Fargo organizes the GD holiday party, and Allison is full of holiday cheer. Dr. Noah Drummer tries to steal a dangerous experiment while a holiday party is underway at Global Dynamic.

Relationships get tested and rescue effort begins to bring Zane and Fargo back from space, in the process all the electronics in Eureka are fried. While in space Fargo shares something about Jo to Zane. In the end Fargo appears before the Technology oversight committee. With the network moving Eureka and Warehouse 13 to the same night.

A new scientist arrives at Eureka, accidentally bringing a new digital virus which uploads itself to Eureka's music system, causing people to act out song lyrics. It is revealed that funding to plan a voyage to Titan is to be granted to Eureka. Beverly makes her return, adding a season plot related twist to the end.

In this interlude. 140 Days remaining until the Astraeus Mission Launch. Scientists compete to be on the Astraeus mission crew for the trip to Titan. Jo and Carter try out contact lenses that predict potential security breaches. At the end, it is shown that the system has flagged Allison's behavior to be a risk.

In this interlude. 115 Days remaining until the Astraeus Mission Launch. Carter has to investigate a Eureka-style bank robbery. Meanwhile, the selection process for the Astraeus mission goes into the next stage. Allison's behavior becomes increasingly erratic and she experiences major gaps in her memory.

Too many aberrations in Allison's now the newly appointed head of GD behaviour leads Carter to suspect that something is wrong. With the help of Zane Donovan and Henry Deacon, they hack Allison's medical records, and finds out that someone is controlling her using nano-technology. This week, we got to see what things are like when the woman of Eureka are running the show.

Carter has to struggle with indestructible machine-bugs threatening to destroy Global Dynamics. These construction mites have been created in order to build and maintain the Astraeus FTL spaceship on the mission to Titan. Unfortunately The experiments in FTL communication has led to a malfunction in the mites, that makes it impossible to control them or shut them down.

Tiny, the Titan rover, is returned to GD after exploring Titan, and bringing samples of the atmosphere, surface etc. However when the compression shield is dropped, Tiny explodes, scattering the samples all over the area. Subsequently, the Eureka atmosphere becomes toxic and the primary toxins are discovered.

Here. The Astraeus candidates go through their final interviews while Carter and Allison appeal their relationship audit. Carter is worried that he might let some memories slip during this process. Warren Hughes accidentally spills coffee which shocks him and distracts Carter from his concentration.

When the FTL drive in GD accidentally activates, sending Andy to Titan, the GD crew must race against time to save him before he is permanently destroyed by the freezing, corrosive atmosphere. Meanwhile, could a spate of meltings all across Eureka that have the entire town baffled be related to Taggart's return.

With five hours before the Astreaus launch to Titan, Carter asks Allison to move in with him, which she later accepts. Deacon finds a slight power shortage in the ship, forcing the countdown to be postponed. It has emerged that the power shortage, along with a number of power arrays across the town, is fueling a number of micro black holes.