Gwen’s older brother, Ken, is missing and Gwen asks for Ben and Kevin’s help to find him. In their search, the gang stumbles upon a Highbreed base in a small town called Santa Mira that manufactures Xenocytes: headcrab-like parasites that mutate humans into DNAliens. Ken has been infected by one of the Xenocytes, but Ben is able to remove it with the help of the voice-automated Omnitrix. With Ken in tow, the gang finds Grandpa Max inside the base. He explains that the Xenocyte eggs will be shipped across the country, and asks the gang to destroy them. While they comply, he sets about destroying the factory while searching for the egg-laying machine.
The gang finds Max locked in battle with a Highbreed Commander upon their return. In an act of self-sacrifice, Max uses an unfocused Null Void warp projector to destroy the Highbreed base. With his last words, he tells Ben to ”Take it from here”. Then everything and everyone, except Ben, Gwen, Kevin and Ken, is sent to the Null Void. In the aftermath, a group of disguised DNAliens are shown gathering surviving Xenocytes from the wreckage of the base.