And Then There Was Ben

And Then There Was Ben is the fifty-second episode of Ben 10: Omniverse.

Plot
With all the other Ben Tennysons across the multiverse wiped out, No Watch Ben is the only Ben remaining. Professor Paradox informs him that in order to undo the damage Vilgax has done, they will have to fix the timestreams. Paradox brings Ben onto Vilgax's spaceship from the original timeline, before the Omnitrix first fell to Earth and was found by Ben Prime.

Paradox explains that due to the damage to the timestreams, Ben Prime never found the Omnitrix. No Watch Ben now must ensure that the events take place as they originally did. As Vilgax chases down Xylene, No Watch Ben transforms into Grey Matter and disables the ship's shields, allowing Xylene's ship to fire a blast and injure Vilgax. The pod holding the Omnitrix is jettisoned, but Paradox notes that its trajectory has been altered and it will not reach Ben Prime. No Watch Ben turns into Cannonbolt, catapulting through an escape hatch and slamming into the Omnitrix pod, sending it back on its destined course towards Ben Prime. Finally, No Watch Ben uses Armodrillo to nudge Ben Prime into the Omnitrix's crater, where the young Ben Prime meets his destiny as the Omnitrix latches onto his wrist. As Ben Prime experiments with Heatblast, Paradox informs No Watch Ben that he must now unite the other good Bens from other dimensions for the ultimate showdown between them, the evil Bens, Vilgax and Eon.

Paradox brings No Watch Ben to a dimension, where No Watch Ben notes that the Omnitrix did not find its way to this Ben either. He is quickly attacked by Gwen 10 as XLR8, and he transforms into Wildmutt to halt her, successfully doing so and allowing Paradox to make his explanations.

The group proceeds to Dimension 23, where Eon is attacking Ben 23, demanding that he joins his forces. Before No Watch Ben and Gwen can intervene, Paradox cautions them that appearing in front of Eon would alert him to their plan and distort the timelines. Gwen is adamant that they help, and No Watch Ben reasons that they must only do so without alerting Eon. A blast from Eon cloaks the area in a cloud of dust, and both No Watch Ben and Gwen seize the chance; No Watch Ben rescues Ben 23 as Gwen takes over as Diamondhead, with Eon none the wiser about the switch. No Watch Ben gives Ben 23 a full update while Gwen attacks Eon ferociously, surprising the villain with her skill. As Gwen is sent flying, Ben 23 switches back in as Big Bug to attack Eon. Eon beats a hasty retreat to find other Bens that are "easier to persuade", and the group of heroes move on. They stop short of recruiting an alternate version of Argit who found the Omnitrix, and instead visit Ben 10,000, who quickly grasps the situation. Ben 10,000 turns No Watch Ben into Clockwork, hoping to use his time powers, but Paradox reminds him that Clockwork creates a ripple effect in time whenever he uses his powers, which Eon is capable of detecting. No Watch Ben decides not to use Clockwork to prevent Eon from being alerted, and the group proceeds to recruit Ben Prime who immediately joins.

In a pocket dimension, Ben 10,000 and Ben Prime give the team a pep talk before Paradox takes them to fight the villains, right at the point where they appeared in the previous episode, but No Watch Ben is shocked when Paradox leaves him behind. He becomes depressed, thinking that he cannot be acknowledged as a hero, but Paradox reappears behind him and reassures him otherwise; Paradox hadn't brought No Watch Ben to the fight because it would have irreparably damaged his own timeline.

Paradox and No Watch Ben re-enter No Watch Ben's timeline just after Vilgax taunted him. Vilgax mocks No Watch Ben, stating that even with an Omnitrix he poses absolutely no threat. No Watch Ben turns into Clockwork and uses his powers to undo the effects of the Chronosapien Time Bomb, restoring all of the other Bens, much to Vilgax's fury. Eon attacks Vilgax for his betrayal, only to be knocked away by Fourmungousaur as the other Bens continue their fight, save for Ben Prime who doesn't have his Omnitrix. No Watch Ben quickly uses Clockwork's powers to send all the evil Bens back to their own timelines, including Eon. Left alone, Vilgax roars at the good Bens in anger. No Watch Ben reverts, takes off Ben Prime's Omnitrix and tosses it back to its owner. Together, the good Bens transform and defeat Vilgax in a series of combination attacks, with No Watch Ben delivering a powerful kick that knocks Vilgax out.

Victorious, Ben 10,000 escorts Gwen and Ben 23 to their respective timelines with Paradox. As the remaining Bens wonder what to do with Vilgax, Max Tennyson shows up to take Vilgax into custody, backed by the rest of Earth's Plumbers. No Watch Ben is thrilled to learn that his grandfather is a "totally awesome space secret agent", as Paradox returns to take Ben Prime back to his proper timeline. Ben Prime is pleased that despite lacking an Omnitrix, No Watch Ben might have turned out to be a hero in his own right. Paradox agrees, remarking on the mysteries of the multiverse and its numerous branched timelines and stories, taking Ben Tennyson home.

Major Events

 * No Watch Ben and Professor Paradox restore the multiverse.
 * Big Bug, Vomit Man, and Eye Guy make their debuts.

Minor Events

 * Ken makes his Omniverse debut.
 * No Watch Ben finds out that his timeline's Grandpa Max is a Plumber.

Characters

 * No Watch Ben
 * Ben Tennyson (10 and 16 years old)
 * Professor Paradox
 * Ben 10,000
 * Ben 23
 * Gwen 10
 * Argit (alternate timeline; cameo)
 * Ken Tennyson (first re-appearance; cameo)
 * Plumbers (alternate timeline)
 * Max Tennyson
 * Jerry (cameo)
 * Bromeba (cameo)
 * Magister Patelliday (cameo)

Villains

 * Vilgax
 * Drones (first re-appearance)
 * Eon
 * Albedo (cameo)
 * Bad Ben
 * Benzarro
 * Nega Ben
 * Mad Ben (cameo)

By 10 year old Ben Prime

 * Heatblast

By Ben Prime

 * Diamondhead

By Ben 10,000

 * Atomic-X (x2)
 * Fourmungousaur

By Albedo

 * Ultimate Echo Echo

By Bad Ben

 * Gravattack (cameo)
 * Buzzshock

By Benzarro

 * Frankenstrike

By Ben 23

 * Eye Guy (first appearance)
 * Big Bug (first appearance)
 * Build-A-Guy (cameo)
 * Vomit Man (first appearance)
 * Electricyeti

By Gwen 10

 * XLR8
 * Diamondhead
 * Wildvine
 * Cannonbolt

By No Watch Ben

 * Grey Matter
 * Cannonbolt
 * Armodrillo
 * Wildmutt
 * Clockwork (x2)

By Nega Ben

 * Gutrot (cameo)

Allusions

 * And Then There Was Ben, along with And Then There Were None, are names parodying the title of the very first episode of Ben 10, And Then There Were 10.
 * Paradox's quote, "There are so many different ways to tell a story, but that's what makes them so interesting; you could never predict how they are going to turn out", is similar to what the narrator said at the end of Gwen 10.
 * The way Argit was swimming in money was the same as Scrooge McDuck from DuckTales.

Trivia

 * This episode is the 200th episode in the whole series in production order.
 * According to Derrick J. Wyatt, And Then There Were None alongside And Then There Was Ben are special episodes that were meant to celebrate Ben 10's 199th and 200th episode ever.
 * Even though this episode is part of the Galactic Monsters arc, it didn't have the Galactic Monsters theme song at the beginning.
 * In one scene, young Ben of the Gwen 10 Timeline is seen sleeping with Ishiyama and Kenko action figures.