Grandpa Max takes Gwen and Ben to a music festival in Chicago to see his favorite old time band, Shag Carpeting, but the event is interrupted by a weather-controlling robot called S.A.M. Ben uses Four Arms to send shockwaves to the robot, eventually destroying him.

While visiting Washington, D.C., Ben confronts Dr. Animo, a disgruntled scientist whose Transmodulator can mutate living animals, and even resurrect dead ones, and eventually learns a lesson about what being a hero really means.

Ben and Max drive to a retirement center to visit their Aunt Vera, but find out that evil shapeshifting aliens called the Limax are kidnapping the residents to eat them later and taking their form to replace them.

The Tennysons come upon a bizarre Christmas village in Death Valley, run by a Christmas-obsessed man (Mr. Jingles), who thinks Grandpa Max is Santa Claus and proceeds to trap him. As Ben and Gwen explore, they learn about a strange curse on the village, in which the village was frozen at Christmas, in the 1930s […]

Clancy, a man who can control insects, wants to take revenge on Councilwoman Liang because she wants to tear down the building where he and his insects live. Meanwhile Ben has to deal with the strange side effects a cold has on his alien forms: Wildmutt is unable to see or smell, Four Arms smells […]

During a trip in St Louis, Ben and Gwen meet a female alien named Xylene, who locates the Omnitrix and confronts Ben under the impression that he had stolen it. But when Max comes to defend them, he and Xylene recognize each other as old comrades and sweethearts. The two reminisce later that night, and […]