If you’re not watching ‘Eureka,’ you’re doing yourself a bit of a disservice. This SyFy original series, now in its fourth season, has never failed to be a light-hearted and fun show that explores many different sci-fi concepts. While I can’t credit it with being wholly original in every episode, that doesn’t seem to matter so much when it comes to the fun ride that the viewer embarks upon every week. With so many science fiction shows out there that tend to be dark and heavy-handed, watching a show that doesn’t take itself too seriously is a welcome breath of fresh air.

Those of us who have been watching from the beginning already know just how addictive ‘Eureka’ truly is. For those of you who haven’t been watching, here is a rundown of the show to get you prepped and ready for Season 4.5, which begins on Monday, July 11.

The town of Eureka is home to the most brilliant minds in the world, all of whom work for a secret company called Global Dynamics. GD, as it’s more familiarly called, is credited with every major innovation since the end of World War II. Eureka itself was founded by Albert Einstein, Julius Oppenheimer and many of the other great scientists of their time as a haven for the great thinkers and innovators of the world to experiment without threat of government intervention. As you will see in the show, their dream was not very long-lived. GD has liaisons from the Department of Defense and other branches of the military looking over its shoulder, trying to determine the most practical military uses for the projects that are developed.

Let’s start by going through the main characters of the show.

Jack Carter (Colin Ferguson) – The story of Eureka is told from his perspective. Carter is a U.S. Marshal who, after crashing his car, stumbles upon Eureka and GD. He quickly becomes the new sheriff, and it’s his ability to see through all the scientific overthinking of problems to a simple solution that, more often than not, ends up saving the day.

Zoe Carter (Jordan Hinson) – She is Jack’s teenage daughter. Saying that Zoe is willful is like saying that Luke Skywalker might have had some unresolved daddy issues. Unlike her father, however, Zoe has the potential to be a Eureka-level genius.

Allison Blake (Salli Richardson) – Allison is GD’s liaison with the Department of Defense. She is a good-hearted woman who oversees most of the operations at GD and works with Jack on all the crazy cases that crop up in town. She has a very dubious flirtation with Jack, and she lives in town with her autistic son, Kevin (Meshach Peters).

Henry Deacon (Joe Morton) – Henry is one of the most brilliant engineers in all of Eureka. Since he has become disillusioned with the level of military oversight at GD, he prefers to work as the local handyman. He does his own experiments in his workshop and is regularly called upon to help when something goes wrong.

Jo Lupo (Erica Cerra) – Jo is Eureka’s only deputy. She and Jack are the ones on call whenever something goes wrong. Being ex special forces, Jo has a tendency to go in guns blazing.

Douglas Fargo (Neil Grayston) – Fargo is a junior scientist at GD. He is overly ambitious and somewhat accident prone. His experiments tend to go wrong, often with disastrous and sometimes hilarious consequences. He is also the creator of SARAH, Jack’s smart home residence in Eureka. SARAH stands for Self Actuated Residential Automated Habitat.

Nathan Stark (Ed Quinn) – Stark is the Director of Research at GD. He is also Allison’s estranged husband. Trying to rekindle the old spark with Allison, he is constantly butting heads with Jack, who is himself trying to date Allison for the first time.

Beverly Barlowe (Debrah Farentino) – Beverly is the town psychiatrist. She is also an operative for a secret consortium of big businesses and corrupt politicians intent on breaking into GD and exploiting their innovations for profit.

Jim Taggart (Matt Frewer) – Taggart is the town loony. He is a very eccentric animal expert who ends up developing a relationship with Jo.

Zane Donovan (Niall Matter) – Zane is a genius fugitive hacker who is “recruited” by GD. Rebellious in nature, it takes some time for Zane to finally fit in with life in Eureka.

Now that you know the main cast, let’s go over what has happened in ‘Eureka’ over the past four years. While many of the episodes are stand-alone, there are larger arcs that continue through the seasons. We’ll focus on that aspect of it. Be warned, this part will contain spoilers, and I apologize in advance if some of my details are off. I am, of course, attempting to condense three and a half years’ worth of a show into a readable form.

Season 1

The main arc for this season concerns an item simply known as “The Artifact.” It is contained in the top security level of GD known as Section 5. The Artifact is emitting intense energy and radiation and must be kept under intense lock and key. Over time, it is revealed that the Artifact is the last remaining piece of whatever existed before the Big Bang. The Consortium, with Beverly as their main agent, is intent on breaking into Section 5 to unlock the secrets of the Artifact themselves.

Stark, a victim of his own ambition, steps up GD’s experiment process on the Artifact, cutting out a piece of it far ahead of schedule. The experiment results in an energy release that ends up killing Henry’s long lost (and recently rediscovered) love, Kim (Tamlyn Tomita). After the accident, we are taken ahead four years to a future where Kim is alive and well, Henry is now the head of GD, Zoe is class valedictorian, and Jack and Allison are married. Their reality is beginning to break down, and it is revealed the Henry, devastated by Kim’s death, had lobbied for Stark’s job at GD specifically so that he could gain access to the Artifact so that he could utilize its temporal properties to send his consciousness back in time and save Kim. The resulting paradox is what is tearing their world apart. The only way to put things right is for Jack to go back and stop Henry from saving her.

In the end, the experiment on the Artifact is a failure. Kim dies, the Artifact loses all of its energy, and Jack and Henry are left with four years worth of memories from an alternate future.

Season 2

With the Artifact dead, Stark is left picking up the pieces and trying to salvage his career. Having to answer for such a costly failure, he is removed as the head of GD, and Allison takes over. Stark still stays on as a regular employee.

Jack and Henry have a very tense relationship since Jack ended up stopping Henry from saving the woman he loved. Both of them are having a hard time reconciling the memories of the alternate future that they have with the way things are progressing differently in front of them. Having had a happy marriage with Allison in the alternate future, Jack is having a hard time handling the idea that they may never get together in this current timeline. Henry resolves this by wiping Jack’s memory, but he refuses to do the same thing to himself. He is determined to get to the bottom of what happened to Kim. Conducting his own investigation, Henry begins to discover clues to the Consortium, Beverly’s connection to it, and her own involvement in Kim’s death.

The big problem is where all the energy from the Artifact went. After the accident, the energy went into Kevin Blake, Allison’s son. While Kevin’s autism has seemed to have subsided, and he has become a more normal boy, the fact that he now has a connection with the Artifact makes him the prime target for the Consortium.

Beverly’s involvement is eventually exposed and she is arrested. Being the kind of survivor that she is, Beverly convinces Henry of Kevin’s importance. Ever the scientist, Henry understands what Kevin is capable of and breaks Beverly out. They kidnap Kevin and Allison and take them into GD’s panic room under the pretense of a flesh-eating bacteria being unleashed on Eureka. In the panic room, Henry plans to use a teleporter to filter out Kevin’s connection to the Artifact. When Beverly learns of Henry’s plans, her own agenda of using Kevin becomes clear.

Jack and Stark are able to penetrate the panic room and stop Beverly from taking Kevin, and they help Henry use the teleporter to fix Kevin. In their joy, Beverly escapes using the teleporter. Even though Henry’s intentions were noble, he is still responsible for causing a biohazard panic in Eureka and is arrested. After everything that has happened with Kevin, Allison and Stark realize that there is still love between them and agree to get remarried.

Season 3.0

This season begins with the Department of Defense sending in a corporate “fixer” named Eva Thorne (Frances Fisher). While her main goal is to downsize GD and make it more efficient – setting all the residents of Eureka on edge – she has a secret agenda that nobody can really pinpoint.

Jack’s free-spirited sister, Lexi (Ever Carradine), comes into town. With Jack already on edge with Allison remarrying Stark and being responsible for carrying out Thorne’s layoffs, Lexi’s presence only makes him more unhinged.

On the big day of Allison and Stark’s second wedding, Jack ends up living the same day over and over again. In the end, the only person who can stop the time loop is Stark, but stopping it ends up killing him.

Thorne recruits Zane to break into a military complex buried underneath Eureka, and Jack begins to grow more and more suspicious about what her true agenda happens to be. The bunker ends up being a vast military complex that was set up before Eureka was founded, and Thorne has become obsessed with wiping it out and removing many remnants of Eureka’s history.

In their own investigation, Jack and Henry discover that there is something that subjected men in the complex to rapid aging. After being trapped in the bunker with friends, Zoe begins developing the same symptoms. Finding some old pictures that Thorne wasn’t able to redact in time, Jack discovers something amazing: Thorne was in Eureka in 1939, and she was attempting to cover up an experiment from then.

Thorne confesses to Jack that she was part of the original nuclear tests in Eureka, and how they created a mysterious byproduct that aged most people rapidly. Thorne, however, was a unique genetic case, and her aging stopped entirely. She has one vial of a cure for the byproduct’s infection, and she gives it to Jack to use on Zoe. The DOD, however, wants to bring in Thorne for what she attempted to do. To repay her kindness, Jack and Henry help Thorne get out of Eureka and start a new life. As a result, Jack is fired from his job as sheriff.

Season 3.5

Jack is applying for a new job at Homeland Security, Allison is pregnant with Stark’s child, and Eureka has a new sheriff: a cheerful android named Andy (Ty Olsson). Jo, having been passed over for promotion twice now, immediately quits. Andy is now the sole law enforcement officer in Eureka. While he has the tools and the know-how, Andy has none of the instinct that Jack and Jo have, and it quickly begins to show with his first case. Through a legal loophole in the town charter – pointed out by Andy of all people – Jack ends up getting to keep his job.

Getting word that something extraterrestrial is heading toward Eureka, Allison brings an old friend into the fold at GD: Dr. Tess Fontana (Jaime Ray Newman). She is a brilliant astrophysicist who quickly catches Jack’s eye. Jo’s on-again-off-again relationship with Zane is finally beginning to solidify into something very real.

The mysterious ship is sending out a signal that hypnotizes the citizens of Eureka to build a landing platform for it. When it arrives, Henry is stunned to discover that it is the Columbus, a deep space explorer that he built and launched with Kim twenty years before. It has returned and could potentially hold the secrets of the universe. He and everybody else are even more stunned when Kim emerges from it. She is an organic construct that the ship made to collect information. GD must use whatever techniques they can find to download all the collected information from Kim’s brain. Ultimately, the only way to remove the information is to destroy Kim, and Henry must deal with losing her yet again.

As Allison goes on maternity leave, Tess takes over as the interim head of GD in her place. While she is good at her job, she knows that it is temporary and takes a job offer in Australia for when Allison comes back. Zoe has been accepted into a prestigious undergrad program at Harvard that begins the next semester. These developments don’t sit well with Jack, but he eventually learns to accept them and deal with life in Eureka without the two of them.

Season 4.0

With Eureka celebrating Founder’s Day, a time machine experiment accidentally transports Jack, Allison, Jo, Henry and Fargo back to 1950 at the original military base upon which Eureka was built. In 1947, they meet Dr. Trevor Grant (James Callis), an assistant to Albert Einstein and one of the founding members of Eureka. Grant learns about their time travel, and sneaks back to the present with them.  The removal of Grant from the early days of Eureka ends up creating an alternate present. The five of them are now forced to acclimate themselves to a world they don’t recognize.

Jack, having just broken up with Tess, now finds himself in a much more strongly committed relationship with her. Jo finds out that, after having accepted Zane’s proposal, in their new reality, he hates her. Allison discovers that Kevin is no longer autistic. Fargo is now the head of GD, and is widely feared by the majority of the staff. And Henry returns home to find that he is married to a woman he doesn’t know. Sheriff Andy also returns, this time as a deputy.

The five from the original timeline make a pact to not tell anybody what has happened to avoid further contaminating the timeline. Henry, however, finds himself in the difficult position of living with his wife, Grace (Tembi Locke), who doesn’t understand why he is behaving so differently. Eventually, Henry breaks down and tells her the truth. Grace leaves Henry, thinking that he is lying, crazy or both. Wracked with the guilt of hurting somebody he doesn’t even know, Henry attempts to woo Grace back and get to truly know her.

Allison helps Grant to get used to the future and he quickly becomes attracted to her, igniting a similar rivalry with Jack to what he had with Stark.  Grant, however, does not feel that he is fitting in all that well in Eureka. Eventually, he catches the attention of Beverly Barlowe and she offers to bring him into the Consortium.

And now you are a well-informed new viewer to ‘Eureka.’ It may not be the greatest science fiction tv show ever created, but what it may lack in originality it more than makes up for in sheer charm. You will be hard pressed to find a more fun and endearing show.  Tune into the SyFy channel tonight at 8pm/7c.