The episode starts with Grandpa Max going to a coffee shop. It's raining. When Grandpa Max enters the coffee shop, it's empty. A woman named Edna greets him and asks him if he wants to see the specials. He says he wants just coffee. She's very suspicious and asks him why he came to Santa Mira. Max lies and claims he came here because of the great fishing and the weather. Then the woman comes with a covered tray and says it's on the house. She opens it and a small parasite-like creature attacks him. He smacks it in the air and starts fighting the woman. He finds out she's a DNAlien after unmasking her.

Meanwhile Ben is begging Kevin for help. Kevin is cleaning his car at the time. He tells him that his cousin, Gwen's older brother, Ken is missing. Kevin doesn't want to help Ben find him, until he finds out it's Gwen brother. He tells them to get in the car. In the car, Kevin learns that Gwen's brother's name is Ken. He makes fun of Ben and Gwen because all three of their names rhyme. Ben reveals that they do rhyme on purpose. Kevin also learns that Ken has a car named the awesome-mobile.

When they arrive at Santa Mira, they look in all the garages. All five garages to be exact. In the fifth one, they find his broken-down car. Kevin makes fun of his car and says it's so bad it makes the Rust Bucket look like a Ferrari. When they break into the garage, they inspect his car and find alien tech and slime in it. Soon after their discoveries, two men come in. They tell the team to live or they'll call the sheriff. One of them is called Shem. When Gwen and Ben find a box of slime, the men get angry. The team soon finds out that they're DNAliens. After fighting against them, Ben turns into Humongousaur and defeats them.

They trace Ken's steps and end up at the coffee shop Grandpa Max was in before. They find a red truck and discover a tied-up DNAlien. After questioning, they find out Ken is being held at the local Hatchery. When they arrive at the Hatchery they uncover some channels of green water.

Meanwhile Ken is being held captive. A DNAlien asks him questions about Grandpa Max, but Ken doesn't know what he's talking about. The DNAlien soon uses a Xenocyte against Ken. At the same time, Grandpa Max is sneaking inside. He defeats a few DNAliens that were in his way and finds Ken in a room. Ken is turning into a DNAlien. Grandpa Max tries to help Ken, but Ken electrocutes him.

Outside, the team enters the water and Kevin is disgusted by it. They discover another weather machine. Kevin is the first one cold once again. Gwen gets attacked by something and goes down. When Grandpa Max wakes up, he is lead to the Highbreed Commander by some DNAliens. He seems calm and asks the Highbreed Commander why he chose to pick Ken. He says he brought him there as bait in order to catch the real prize. He wanted Max Tennyson. The Highbreed Commander also tells Max some secrets about the Xenocytes, and their plans.

Meanwhile Gwen frees herself from the Xenocytes that brought her underneath the water. The team dives into the water and when they come up for air, DNAliens spot them. They start fighting the DNAliens. Ben turns into Big Chill and freezes a couple of them. Gwen notices Ken's face on one of the DNAliens. She stops Kevin and Big Chill from attacking him. The Omnitrix detects DNA damage and brings Ben into it. Ben is confused and doesn't know what to do. He follows the Omnitrix's plans and frees Ken from the Xenocyte.

Ken soon helps the team find Grandpa Max. He is extremely glad to see all of them including Kevin. He tells everyone how proud he is. Grandpa Max tells Ben to run off and stop the DNAliens from transporting the Xenocytes. Ben asks Grandpa Max what he's going to do, and he replys back by saying what he has to. The team along with Ken go outside and start fighting the DNAliens.

They destroy most of the trucks and break open the Xenocyte eggs. Ben turns into Jetray to make the job faster and easier. Gwen releases all her anger and creates massive damage. Ken notices bright light coming out of the Hatchery. They all go inside and are surprised to see all the damage Grandpa Max made. They find him fighting the Highbreed Commander.

Ken yells at the Highbreed Commander and tells him to release his grandfather. The Highbreed Commander refuses, and threatens them by saying he's going to kill him. He picks up Grandpa Max. Grandpa Max pulls out his Null Void projector. He dismantles half of it and says it would act as a hand grenade. He predicts that it would take out everything up to half a mile from where they are. The Highbreed Commander doesn't believe him and dares him. Grandpa Max tells Gwen to throw an energy field around the team. He then presses the button and everything blows up.

When Gwen lets go of the energy field, they all start talking. Kevin says that the action Max took was hardcore. Gwen says he's a hero. Ben doesn't have his hopes up though. He claims that it's not over and that more DNAliens will come.

When the sun rises and it's all over, some men are uncovering Xenocytes under all the rubble and metal. They throw them into garbage bins. Then lightning is shown, along with their true identities. They're all DNAliens.