Star Trek Prodigy's Use Of Time Travel And Causality, Explained As Simply As Possible

"Star Trek: Prodigy" was initially billed as a Trek series for younger audiences. It was released not by Paramount, but by Nickelodeon, and the main characters were all teenagers, learning about the existence of Starfleet for the first time. A hologram of Captain Janeway (Kate Mulgrew) was there to usher the teens toward a life of decency and heroism, and also to assure Trekkies that this show did connect to extant Trek lore at large. 

That said, the plot of the show's first season was somewhat complicated, and made use of unusual time travel conceits that a younger audience might have trouble wrapping their heads around.

The plot centered on the mystery of a lost and abandoned Starfleet vessel called the U.S.S. Protostar. The ship was found by Dal R'El (Brett Gray), Gwyn (Ella Purnell), and a few other teens who were escaping slavery. They fled in the Protostar, chased by the Diviner (John Noble) a bitter villain and their former owner. While the teens learned about Starfleet from Hologram Janeway, the Diviner desperately sought the Protostar for his own nefarious ends. 

It was eventually revealed that the Diviner's homeworld will, at some point in the future, be visited by the Federation to engage in First Contact. Typically in "Star Trek," First Contact is a mind-opening experience for the species that experiences it, and entire planets tend to unify once they know they are part of a larger, galactic community of aliens. For the Diviner's homeworld Solum, however, First Contact instigated a vicious Civil War between the planet's progressives and xenophobes. Eventually everyone was killed.

The Diviner — real name Ilthuran — helped invent an unbeatable, self-destructive computer virus called the Living Construct, and escaped 52 years into the past ... Well,the plot only gets more complex from there.

And we're not even done with the first season. 

But to continue: the ship that went to Solum to engage in First Contact was the U.S.S. Protostar, commanded by Captain Chakotay (Robert Beltran). After First Contact, the Protostar flew through a wormhole that deposited it 52 years in the future, where it subsequently witnessed the devastating effects of the Solum civil war. The Diviner captured the Porotstar and armed it with the Living Construct — a virus that causes Federation ships to automatically attack each other — hoping to send it back to its original time and prevent First Contact. Chakotay instead sent the ship back 52 years through the time hole, and aim it out into a random spot in space. 

The Protostar landed near the mining colony where Dal and his friend were imprisoned, and that's where "Prodigy" begins. The first season ended with the Protostar kids overcoming the Diviner, uncovering his plan, and returning to Federation space. 

Chakotay, however, was still stranded 52 years in the future. At the beginning of the second season of "Prodigy," the real-life Janeway sets off on a rescue mission in a new ship, the Voyager-A. Dal and co. are now Starfleet trainees, and are allowed to come along. Janeway explains to the audience that the time hole Chakotay flew through is still out there in the same location, but that it's unstable and may collapse soon. She has to work fast. 

Also, and this is notable, time moves forward at the same rate on the other side of the wormhole, so if an hour passes in the present, an hour also passes 52 years in the future. Chakotay has been in the Diviner's future prison for a while. 

Dal can barely wrap his head around the above descriptions, and moans constantly that he hates temporal mechanics. Luckily, in the fourth episode of season 2, called "Temporal Mechanics 101," Dal has the time to study a crash course on temporal mechanics, hosted by a helpful Starfleet officer in a blue uniform. She explains everything he needs to know, and Dal is able to grasp — just barely — the time travel plot. 

So it seems Janeway, using a time-shielded runabout called the Infinity, intends to go through the time hole and rescue Chakotay. Easy to understand.

Thanks to some dramatic goings-on, Dal and the "Prodigy" kids fly through the time hole on their own, sans Janeway. Surprisingly, they find themselves next to Chakotay after he had been overwhelmed by the Diviner's forces, but before he had a chance to wrest the Protostar back. Because of a weird case of reverse causality, Dal finds that he had to let Chakotay send the unmanned Protostar back through the wormhole before Dal can stage his rescue. It's all very complicated. 

Meanwhile Gwyn tries to prevent a civil war on Solum by going there ahead of the Protostar ... in the present day ... to prep the planet for what's to come. She's a pre-First Contact diplomat now. Because she's now in the present, however, Gwyn is displaced in time; she actually won't be born for a few decades yet. While on Solum, she meets the younger version of the Diviner, back when he was idealistic and peaceful. She has a chance to redeem him. 

So the plot of "Prodigy" involved two time frames: the present, and 52 years in the future.

Now the story can begin.