Ben Ultimate Protect of Earth is a game based on the TV series.

Ben tracks the rest of his alien DNA to a re-enactment of the Civil War at New Orleans, and while searching, the Tennysons are attacked by Dr. Animo's mutants. To make matters worse, Animo kidnaps Gwen. After tracking and defeating Clancy at a bayou, they learn from him that Animo is planning on turning Gwen into a mutant, along with the rest of the world. Tracking Animo to an abandoned oil refinery, where it is secluded and has sufficient power for his machines, Ben fights and defeats him, saving Gwen. They learn from Gwen that Animo partnered with Vilgax as well, and is planning to send the entire Earth into the Null Void using the stolen Plumber Technology that is powered by alien DNA. After beating Animo, Ben gets the Master Control of the Omnitrix.

As Vilgax is repaired by his nanobots in the Null Void, he swears that he will return someday. The last area is the Null Void where Ben fights all of his enemies again. In the final scene, Gwen tells Ben how impressed she is, while Grandpa Max looks for a way out of the Null Void.