Deuce bumps his head one too many times and winds up with amnesia. Not only does he not know who he is, but he doesn't even know he's a butt! Eleanor decides this is the perfect opportunity to create Deuce 2.0, but Zack just wants his bud back. They scramble back and forth, each trying to remake Deuce. But neither of them notices they've left Deuce sitting in front of the TV watching a Bummy Rippa movie and suddenly – Deuce now thinks he's a butt fighter! And he's pretty awesome at it too! In fact, soon, Silas invites him to join the B-Team. Now, Zack and Eleanor need to switch Deuce back before he steals their rightful place in the greatest buttfighting squad of all! Thanks to one of Deuce's psycho episodes, Zack winds up with a face that looks like a butt! And lo and behold, he (and Deuce) get invited into a top secret, butts-only club, the famed Skull and Bums. It's the stuff of legends. Eleanor and the butt fighters have wondered about the rumours for years and now – Zack is in! And he gets to see what butts act like when no one is around (it's not pretty). Soon, Zack's swelling goes down and he and Deuce must find ways to re-create his 'butt face' and get back in. And when he does, he needs to find out just what the butts are up to. Eleanor says there's an evil plan. So there must be.