Ben 10 Secret of The Omnitrix

During a battle with Dr. Animo, the Omnitrix is accidentally set to self-destruct. In order to stop it, Ben has to travel across space to track down the Omnitrix's creator. Three alternate versions of this have aired, each with a modified opening from the original. Actually an episode which made up the first three episodes of season 4.

Ben 10 season 4 episode 10 : The Lost Episode: Goodbye and Good Riddance

In this non-canon episode, Ben returns home after the summer vacation ends, and is told by Max that he must keep the Omnitrix a secret. This is made more difficult with his classmates admiring the alien heroes that they've seen on the news, unaware that it is Ben himself. Initially disappointed, Ben gets the chance to use the Omnitrix when Vilgax attacks, yet again looking to take the device from Ben. All four Tennysons (Ben's father helps) fight off Vilgax's drones running amok in the city. When Vilgax appears again, easily fending off Ben, Ben's father suggests leading him into the underground gas line, which they ignite to incinerate the villain. Ben's secret is revealed to the public during the affair, and Gwen ends up transferring to his school. Just when it seems like everything is quiet, Dr. Animo shows up with a cadre of mutated animals, which Ben and Gwen get ready to fight.

Ben 10 season 4 episode 9: Ben 10 vs. the Negative 10 (Part 2)

Ben, Gwen, and Max, along with Cooper, use the Plumbers' Mount Rushmore installation to mount a final stand against the Forever King's forces. Max discovers that the Forever King was once a plumber named Driscoll who was kicked out after hoarding alien technology. Despite their best efforts, they are unable to keep Driscoll from obtaining the Sub Energy. Driscoll uses the energy to enhance his armor suit and battles Ben, who is able to use Upchuck to digest the power source and destroy it safely (he obliterates the Mount Rushmore faces in doing so, however).

Ben 10 season 4 episode 9 : Ben 10 vs. the Negative 10 (Part 2)

Ben, Gwen, and Max, along with Cooper, use the Plumbers' Mount Rushmore installation to mount a final stand against the Forever King's forces. Max discovers that the Forever King was once a plumber named Driscoll who was kicked out after hoarding alien technology. Despite their best efforts, they are unable to keep Driscoll from obtaining the Sub Energy. Driscoll uses the energy to enhance his armor suit and battles Ben, who is able to use Upchuck to digest the power source and destroy it safely (he obliterates the Mount Rushmore faces in doing so, however).

Ben 10 season 4 episode 8 :Ben 10 vs. the Negative 10 (Part 1)

The Tennysons pick up the grandson of another Plumber named Cooper, who is hitching a ride home with them. Meanwhile, a Plumber base at Fort Knox is robbed by the Circus Freaks and Sublimino. By the time the Tennysons find out, they are too late to help. They soon learn of a second robbery, this one run by Rojo (having gained a new cybernetic suit), Animo, Clancy (mutated into an insect), and Charmcaster. Max discovers that they are searching for the keys to the "Sub Energy", an extremely potent sub-atomic power source given to the Plumbers by an alien race. they lose the keys to the villains, and attempt to route them at the Mount Rushmore base, where the Sub Energy is stored. However, they find that the Forever King, joined by a subordinate and the villains that raided the earlier bases, has beaten them to it. He dubs his team the Negative 10 and sets them upon the Tennysons.

Ben 10 season 4 episode 7 : Ken 10

In the future, Ben's son Ken is celebrating his tenth birthday, and to commemorate the occasion Ben gives him an Omnitrix of his very own. However, he equips it with a limiter, unwilling to trust his son to defeat villains on his own. Ken soon befriends a boy named Devlin, and the same night Kevin 11 attacks. Unable to locate the Null Void, which Ben has moved after the events of "Ben 10,000", he retreats. Ken, also unaware of the move, endeavors to find it on his own, only to unwittingly lead Devlin, who is Kevin's son and can transform into his father's mutant form, right to it. Devlin releases his father from the void, but is soon heartbroken to learn that Kevin's only interest is in fighting Ben, not in seeing his son. Kevin is ultimately defeated by the combined forces of Ben 10,000, Ken 10, and Devlin 11, who is later adopted into the Tennyson family.

Ben 10 season 4 episode 6 : Ready to Rumble

After damaging Gwen's laptop, Ben enters a mutant wrestling competition as Fourarms to earn some money to replace it, becoming an instant celebrity. During the tournament, he fights a pair of mutant brothers who owe a mob boss a large sum of money in order to save their farm. They entered the competition in order to pay off their debt, which Ben doesn't learn about until after defeating them. After learning the truth, Ben goes with them to save their mother, who is being held by the gang as "collateral". After rescuing her, Ben gives the prize money to the family since they need it more than he does. Returning home, he admits to what he did, only to discover that the computer wasn't even broken in the first place, requiring a special key that Gwen had to activate it.