Secrets is the thirteenth and final episode of the first season of Ben 10 , and the thirteenth episode overall. Grandpa Max 's mysterious past comes to light when Vilgax shows up on Earth in search of the Omnitrix. And the family must work together to defeat him. A news-station helicopter is following police cars chasing a speeding armored car. The reporter says that criminals hijacked the car from a bank, and they have a hostage.
Along the highway, they speed past Max's RV and a large crystal grows out from the pavement, completely destroying the undercarriage of the car. The effect makes it spin and completely stop. One of the criminals gets out of the vehicle with the hostage, and the other, holding a rather large rifle. He aims his rifle at the police car and shoots it and it flies into the air, just after the police inside it goes out.
He directs it toward Diamondhead , though he doesn't seem to be afraid of it, and slashes it to pieces. The criminal runs away in terror, but he's stopped by another crystal emerging from the cement, lifting him up. The first criminal walks out from behind with the hostage. Diamondhead is silent and he transforms his hand into a spike.
With that appearance, they surrender immediately, and the news reporters comment on Diamondhead's heroic act. They seem to say that heroic aliens have become a common occurrence. Vilgax is watching the broadcast in the Chimeran Hammer. He's displeased with how the Omnitrix is being used for heroics since he intends to use it for his own selfish agenda.
His robotic lieutenant asks Vilgax if he's allowed to send more Mechadroids to retrieve it. Vilgax replies with a no, and his regeneration tank opens. One of the medical robots crawls out, only to be crushed by a massive metal foot. Vilgax's limbs have fully regenerated, and he says that he'll see to the task himself. In the Rustbucket, Ben wakes up screaming. Max asks him if he had another nightmare. He recaps that he's been dreaming about the weird alien from his vision when he merged with Rojo as Upgrade.
