Season 4
Episodes
1. Perfect Day
Enoch and the Forever Knights return, putting Ben in a dream world where he's tricked into having the perfect day. However, his dream quickly turns into a nightmare.
2. Divided We Stand
Ben gains another Omnitrix hero to use, which he calls Ditto. Gwen can't stand being around the multiplying Dittos, and they end up giving her headaches. The Dittos, though, prove to be real helpful against Dr. Animo and his multiplying Stinkflies after he extracted some of Ditto's DNA.
3. Don't Drink the Water
After being in contact with water from the Fountain of Youth, Grandpa Max and Ben are reverted to being kids again. Now, Gwen is left to take care of them while stopping Hex from finding the fountain's source.
4. Big Fat Alien Wedding
Ben, Gwen, and Grandpa Max attend a family wedding. During the ceremony, a strange alien attacks. Will the two ever finish this strange wedding?
5. Secret of the Omnitrix (1)
During a battle with Dr. Animo, the Omnitrix is accidentally set to self-destruct. In order to stop it, Ben, Gwen, and Tetrax travel across space to track down the Omnitrix's creator, Azmuth.
6. Secret of the Omnitrix (2)
During a battle with Dr. Animo, the Omnitrix is accidentally set to self-destruct. In order to stop it, Ben, Gwen, and Tetrax travel across space to track down the Omnitrix's creator, Azmuth.
7. Secret of the Omnitrix (3)
During a battle with Dr. Animo, the Omnitrix is accidentally set to self-destruct. In order to stop it, Ben, Gwen, and Tetrax travel across space to track down the Omnitrix's creator, Azmuth.
8. Ben 4 Good Buddy
While on a desert highway, the RV gets stolen by a group of modern-day pirates, who use it to go on a robbery.
9. Ready to Rumble
When Ben accidentally breaks Gwen's laptop, he participates in the "Ultimate Wrestling Competition" as Four Arms to get the prize money for a new laptop to replace Gwen's broken one.
10. Ken 10
In the future, Ben gives his son, Ken, an Omnitrix for his 10th birthday. However, Ben will have to learn to trust him with that power.
11. Ben 10 vs. Negative 10 (1)
Ben, Gwen, Cooper and Grandpa Max face their last battle ever against the villains they have encountered and they will battle to get the world's most powerful energy source.
12. Ben 10 vs. Negative 10 (2)
The Forever King sets his plan in motion and recruits the most powerful enemies Ben has ever faced in order to steal the world's most powerful energy source.
13. Goodbye and Good Riddance
The summer finally ends. Ben and Gwen have to go back to their normal lives. Grandpa Max tells Ben to keep the Omnitrix a secret from everyone, even his parents. Ben agrees, but Vilgax arrives and he'll stop at nothing to get the Omnitrix.