After the incident with Vilgax, Grandpa Max tells Ben and Gwen about his secret past. He really was a plumber, but not the garden variety version. He was part of a secret government organization known as “The Plumbers,” that dealt with extra-terrestrial and paranormal phenomenon that others couldn’t. The organization was disbanded after he defeated Vilgax for the first time. During one of Ben’s regular acts of heroism, they run into Max’s old partner, Phil. Phil is still in the business of hunting aliens, though he is now a freelance agent. He suggests that they remake The Plumbers, but Max is against the idea. Ben, however, is much more enthusiastic about the idea.
During another alien battle, Ben reveals the secret of the Omnitrix to Phil, and Phil is even more determined to get him as a partner. Phil ends up taking them to an expensive hotel, which he is able to pay for thanks to rewards for capturing the aliens. The frequency of the alien attacks, as well as the familiar aliens themselves, raises Max’s suspicions, and he heads to Mount Rushmore to check on something. There, he finds the Null Void Projector—a weapon that can trap things in, or release them from, an alternate dimension—missing. Phil has been abusing it to scam various hotel owners into paying him to remove the aliens that he sets free. Phil releases an alien to deal with Max, but Ben is able to rescue him and eventually trap Phil in the Null Void.