Season 1
Episodes
1. And Then There Were 10
Average kid, ten year old Ben Tennyson, his Grandpa Max and his cousin Gwen's summer of adventure takes an odd turn when Ben discovers a watch like object that has been jettisoned from alien spacecraft high above the Earth.
2. Washington B.C.
Ben must fight Dr. Animo, a crazed scientist who has a DNA-altering device.
3. The Krakken
Ben has his hands full with a giant sea monster and an evil poacher.
4. Permanent Retirement
Ben must rescue his aunt and grandfather when they are held hostage by shape-shifting aliens.
5. Hunted
Ben is pursued by three bounty hunters sent by Vilgax to steal the Omnitrix.
6. Tourist Trap
Ben accidentally releases creatures made of electric energy and must use his own powers to recapture them.
7. Kevin 11
Ben meets a mutant who can absorb any form of energy and may be after the Omnitrix.
8. The Alliance
Ben clashes with a female gang member who's become part cyborg.
9. Last Laugh
Ben discovers an evil circus that's headed by a psychic vampire clown named Zombozo.
10. Lucky Girl
Ben battles a sorcerer who possesses a number of charms, and Gwen suddenly becomes a superhero when one of the charms falls into her hands.
11. A Small Problem
Ben gets revenge on an amusement-park attendant who said he was too small to go on a ride.
12. Side Effects
Ben's summer cold causes strange physical changes in his alien personas.
13. Secrets
Vilgax tries to get the Omnitrix for himself while Grandpa Max's strange past becomes known, causing a showdown between Vilgax and the Tennyson family.