Mud is Thicker Than Water

While Rook and Kevin are at an auto show, Ben, Gwen, and Cousin Lucy (who is the first of her kind to become a Plumber) try to find out how Psyphon's thugs are getting Level 7 Plumber technology. Gwen suspects that Lucy is the mole because of her shapeshifting abilities as a Sludgepuppy, and her love of tricks when she was younger, but it turns out that it is an old enemy: Gorvan.