When Ben isn’t tall enough for a ride at a water park, he decides to change into one of his alien forms to get even with the ride attendant. Unfortunately for him, the Omnitrix malfunctions and he ends up as Grey Matter. To make the situation worse, he is captured by an alien fanatic name, who decides to trade him in for fame and glory. Now Ben, as Grey Matter, must find a way out of this predicament, after being given to a secret organization for testing.