After Ultimate Alien, Ben gets a new Omnitrix along with a new set of aliens. While Gwen and Kevin go off to college, Ben is ready to become a solo superhero. But Max pairs him up with a by-the-book rookie plumber, Rook Blonko. Max sends Ben and Rook to investigate a hidden alien city. Meanwhile, Ben is targeted by an intergalactic bounty hunter named Khyber. Ben later meets new villains and has a secret about his alien Feedback.