Season 3: the Ultimate secrets revealed, all new villains, and the return of the Nanochips, along with a whole new set of ten aliens. This is gonna be good!
Two New Crooks
When a Gourmand without a known name and a Pisciss Volann named Fich show up, Ben and Co. try to get to the bottom of this.
Return of the Nanochips
The Nanochips are back. Can Ben and Co. stop them?
Vulkanus, now a regenerated cyborg, is trying to blow up Petropia to get its Taedenite. Can Ben and Co. stop him in time?
Ultimate Kate, Part 1
Crossover: Kate Underlocke, teamed up with the Nanochips, attacks Ben Tennyson. It would be a lot easier for Ben to beat her if she didn't mutate into evil monsters and random times! Can Ben and Co. stop her?
Ultimate Kate, Part 2
Kate has been mutated into a fusion of all of her mutations (sound familiar?). Can Ben and Co. stop her now, or will they have to do the unexpected?
More DNA Taken
The Gourmand, now revealed to be named Zeno, is stealing more DNA from the Codon Stream. Now it's revealed that he's working with the Nanochips! Can Ben and Co. beat him after he turned himself into the aliens of the DNA he stole?
Ben 10: Phineas and Ferb Style!
Non-canon episode: Ben and Co. are fighting Sevenseven, and Will Harangue is trying to get the "Hate-Ben 10" club to see the battle themselves. Meanwhile, Max fights the regenerated Vilgax.
Is It Validus?
Victor Validus has been spotted with the Nanochips again. But Ben and Co. learn the truth: someone is framing him with an ID mask! Who is this mysterious villain?
Super Tennyson Bros.
It's-a me! Ben Tennyson! Ben and Co. are sucked into a Mario-parodying game called Super Jario Bros. But the real Vilgax--the other one was a clone from Albedo's Omnitrix--has teamed up with Jowser! Can Ben and Co. survive in the world of Jario?
Return of Clancy
Yep, Clancy's working with the Nanochips, too. Can Ben and Co. stop him, plus Zeno and Fich?
Dawn of... Evil Ben! Part 1
After Ben unwillingly ruins the path of time by putting it into a different crosstime path, he must face the evil version of himself, dubbed Evil Ben. Can he survive against himself?
Dawn of... Evil Ben! Part 2
Ben must trick Evil Ben in order to defeat him. Can he come up with something good enough to work?
Paparo kidnaps Azmuth and Ben before he can finish explaining the Planetary Connection to Ben and Co. Can Gwen, Kevin, Albedo, and Myaxx stop Paparo, now enhanced by the Nanochips?
New alien. From Jario. Enough said. Wait, these summaries are supposed to end with questions, so... how do you think it will work out?
Ben finds himself fighting every villain he ever faced, right after a series of strange events. What made Ben's day so weird?
Can Ben and Co. stop Paparo before he completes his plan?
Playing With Mud
Argit, after a stupid bet with Vulkanus, frees Mr. and Mrs. Mann. Can Ben and Co. defeat them?
Say Goodbye to the Chips
Ben and Co. call upon Victor and Elena Validus to help them defeat the Nanochips for good, slowing down Paparo. Can they all handle such a task?
The Beginning of the End, Part 1
It's time. Can Ben and Co. manage to stop Paparo once and for all before Part 2 rolls around?
The Beginning of the End, Part 2
Season Finale: No, they couldn't stop him in time. But there's still some hope. Can Ben and Co. stop Paparo's backup plan now that they've stopped his original?
Below is "Season 3.5", somewhere between Seasons 3 and 4. It's only a crossover movie, but a huge one!
Ben 10: Ultimate Crossover
Vilgax is back, and he drags the heroes of many series into the second BTMT movie. Can Ben and the other heroes stop him from taking revenge?