And Then There Were None

And There Were None is the fifty-first episode of Ben 10: Omniverse.

Plot
The episode starts with Ben walking on the street. Suddenly, he hears a woman screaming for help whose cat got stuck in a tree. Ben helps the cat and starts to think about what is like to be a superhero. He then realizes that he is late for his soccer game and looks at his broken watch, revealing that this universe is the one where Ben never received the Omnitrix. At the game, Ben is the goalkeeper, but unlike in the main timeline, they won because of a player hit the goalpost in the last minute. Following the match, Ben gets robbed by Kevin Levin who takes his broken watch. He then meets his grandfather who came to pick him up with the Rust Bucket.

Max asked Ben why he was so gloomy in which he replies that he is bored of the same old routine in the same old town and that he wants something exciting to happen. Max told Ben that he does not need to find it, it will find him. When they made it home Ben was surprised to see his cousin to be on their couch. They had a short, awkward talk until J.T. called Ben asking him to come to Mr. Smoothy's.

Shortly after leaving, Ben realizes he's being followed and walks into a dark alley to throw his pursuer off. His pursuer reveals himself to be Bad Ben, who looks just like him only with black hair. While Ben is in disbelief, Bad Ben declares that Ben must be destroyed and transforms into Ghostfreak and starts to chase Ben. Bad Ben is soon joined by Albedo and Benzarro, who respectively attack him as Ultimate Humungousaur and Frankenstrike. Cornered, Ben is saved just in time by Ben Prime, who ropes him away using Spidermonkey and promises him to take him to someone who can help.

At Los Soledad, Professor Paradox makes his appearance in front of the two Bens, explaining to Good Ben the concept of the multiverse; an infinite number of Ben Tennysons exist through multiple versions of the universe, but someone has been kidnapping them. Good Ben is an anomaly, as he is the only Ben Tennyson who never even heard of the Omnitrix, and he is being targeted for an unknown reason. Ben Prime is certain that Eon is behind the kidnappings, but Paradox notes that Eon would never leave tracks behind, suggesting that Eon works for a higher power. Paradox departs, instructing Ben Prime to protect his defenseless counterpart.

No sooner than Paradox leaves, Eon shows up to attack Good Ben, forcing Ben Prime to turn into Wildmutt and defend him. Ordered to escape, Good Ben runs for his life but comes across Vilgax, who reveals himself to be the one working with Eon. Vilgax tells them that he and Eon have been kidnapping Ben Tennysons across the multiverse to corrupt them, giving Vilgax control of an army of Omnitrix-wielding warriors. Bad Ben, Albedo, Benzarro, Mad Ben and Nega Ben all reveal themselves. Vilgax states that Good Ben, though lacking an Omnitrix of his own, is a wild card that must be eliminated.

Before the evil Bens can destroy the two Bens, Paradox shows up with reinforcements: Ben 10,000, Ben 23 and Gwen 10. The good and evil Bens go alien to fight it out, while Ben Prime tells Good Ben to escape and hide. Good Ben is constantly stopped by the evil Bens, but is saved every time by an ally until Eon chases him down. Ben Prime swoops in as Astrodactyl and takes Good Ben to safety. Good Ben laments his lack of an Omnitrix, however, Ben Prime simply tells him that "it's just a gadget", and simply having the Omnitrix doesn't make him a hero.

On the top of a building, Vilgax watches the battle. Eon approaches him and asks why Vilgax isn't fighting. Vilgax retorts angrily that Eon is in no position to make demands and orders him to open the portal. Eon grudgingly complies, and Vilgax pulls out a bomb through the portal. Eon reminds Vilgax of their partnership and points out he wasn't informed about a bomb; Vilgax answers that the bomb is a Chronosapien Time Bomb, and begins activating it. Eon gleefully notes that Vilgax intends to erase Good Ben from existence with the bomb, but Vilgax corrects him. The bomb will not affect Good Ben or his timeline, instead it will erase every other Ben Tennyson from existence. Eon blanches, remembering that he himself is an alternate version of Ben, and Vilgax calmly thanks Eon for his help and tells him that his assistance is no longer required. As the bomb activates, Eon tries to escape but is swallowed up by the blast. Good Ben notices the blast and turns to ask Paradox for advice, however, the Professor is gone. The blast spreads, wiping out the other Bens one by one, save for Ben Prime who regroups with Good Ben, heroically shielding him from the blast. As Ben Prime fades into non-existence, his Omnitrix falls onto Good Ben's wrist and connects. Ben Prime instructs Good Ben to "be the hero" as he fades away.

Good Ben is soon attacked by Vilgax who manages to conceal the Omnitrix on his wrist from Vilgax's sight. Vilgax gloats that this was the sole reason he hunted down Good Ben; to destroy all the wielders of the Omnitrix at once. Declaring that Good Ben is no threat to him, Vilgax attacks, but Paradox pulls Good Ben to safety via a portal. Vilgax taunts Good Ben, declaring that he is doomed to run away in fear of Vilgax for the rest of his life.

In a pocket dimension, Paradox confirms that Vilgax's actions have killed off all other Ben Tennysons in the multiverse, leaving Good Ben as the last remaining Ben Tennyson. Good Ben sadly looks down, but regains a determined look on his face, ready to face whatever comes next. Paradox cryptically informs Good Ben that they will have to return "to the beginning".

Major Events

 * Good Ben, Bad Ben, Mad Ben, Nega Ben, and Benzarro make their debuts.
 * Gwen 10 makes her canon debut.
 * Build-A-Guy, Fourmungousaur and Atomic X make their debuts.
 * J.T. makes his Omniverse debut.
 * Every timeline and Ben (with the exception of Good Ben and his timeline) get wiped out by a Chronosapien Time Bomb.

Characters

 * Good Ben (first appearance)
 * Ben Tennyson
 * Ben 10,000
 * Ben 23
 * Gwen 10 (first appearance)
 * Professor Paradox
 * Max Tennyson (alternate timeline)
 * Gwen Tennyson (alternate timeline)
 * Kevin Levin (alternate timeline; cameo)
 * J.T. (alternate timeline; cameo)
 * Madison's Father (alternate timeline; cameo)
 * Natalie Alvarez (alternate timeline; cameo)
 * Old Lady (alternate timeline)

Villains

 * Vilgax
 * Eon
 * Albedo
 * Bad Ben (first appearance)
 * Benzarro (first appearance)
 * Nega Ben (first appearance)
 * Mad Ben (first appearance)

By Ben

 * Spidermonkey
 * Wildmutt
 * Astrodactyl

By Ben 23

 * Build-A-Guy (first appearance)

By Ben 10,000

 * Fourmungousaur (first appearance)
 * Atomic X (first appearance)

By Nega Ben

 * Gutrot

By Mad Ben

 * Rath

​By Gwen 10

 * Wildvine

By Benzarro

 * Frankenstrike
 * Snare-oh

By Albedo

 * Ultimate Humungousaur
 * Ultimate Spidermonkey

By Bad Ben

 * Ghostfreak
 * Gravattack

Errors

 * In one scene, Ghostfreak's Omnitrix symbol is the same color as his chains.
 * Vilgax mentions fighting Ben for a decade, but he has only been fighting him for 6 years.
 * When Eon throws a grenade at Prime Ben and Good Ben, the 10 on Ben's shirt is green.

Allusions

 * And Then There Were None, along with And Then There Was Ben, are names parodying the title of the very first episode of Ben 10, And Then There Were 10.
 * "And Then There Were None" is the title of a mystery novel by Agatha Christie.
 * When Benzarro said, "Ben smash!" he was referencing The Hulk's catchphrase, "Hulk smash!".
 * When Good Ben said "Strange things are afoot at the Mr. Smoothy's.", he is referencing a line from Bill & Ted's Excellent Adventure when Ted Logan said "Strange things are afoot at the Circle K."

Trivia

 * Even though this episode is part of the Galactic Monsters arc, it didn't have the Galactic Monsters theme song at the beginning as it was aired a part of the following season.
 * The old lady referenced the meme "Can I haz cheeseburgar" while talking to her cat, ironically, both situations involves cats.