Ben 10 - S02 - Ep 1

Shortly after the events of "Secrets", Max tells Ben and Gwen about his secret past; he was a deputized agent of "The Plumbers", a secret government organization that dealt with extraterrestrial phenomenon, which was disbanded after Max defeated Vilgax himself for the first time. They run into Max's old partner, Phil Billings, who is still hunting aliens, though he is now a freelance agent. The frequency of the alien attacks and the familiar aliens raises Max's suspicions, and he heads to Mount Rushmore, where he finds the Null Void Projector—a weapon that can trap things in, or release them from, an alternate dimension—has gone missing. Phil has been abusing it to scam various hotel owners into paying him to remove the aliens that he sets free.

Ben 10 - S02 - Ep 1

Ben 10 - S02 - Ep 2

Ben 10 - S02 - Ep 11

Ben 10 - S02 - Ep 12