10-year-old Ben Tennyson begins summer vacation with his 10-year-old cousin Gwen and his grandfather Max. He wanders off and finds an alien pod that has crashed to earth, and within it a watch-like alien artifact. When he reaches to touch it, the watch jumps onto his wrist and refuses to come off, merging with his DNA. Ben accidentally discovers that it can change his form into various alien creatures and quickly learns how to use it, protecting people from robots sent by Vilgax to retrieve the watch. Deciding he can be a real-life superhero, Ben begins a summer full of extraterrestrial adventures for himself, Max and Gwen.