The Titans prevent an invasion from another dimension that occupies the same space as Chet Walters' school.
Atop the Hillsdale High School rooftop, the Teen Titans eavesdrop on a conversation between Chet Walters, his father, and Principal Downs. Walters desperately tries to convince the older men that the school will soon become the beachhead for an invasion force from another dimension. His pleas falling on deaf ears, Walters leaps through the window, to escape being taken to a clinic "for observation". Wonder Girl takes off after Walters. As Walters races through the school grounds, he is taunted by his classmates, including his own girlfriend, none of whom believe in Walters' wild stories. Wonder Girl grabs Walters and brings him to the Teen Titans.
Walters explains that while he was painting graffiti on the side of the water tower, he was drawn to a glowing, green button. Pressing it transported him to an exact replica of the school, occupying a parallel dimension. There he learned of the plot to invade the Earth. Walters fled the alien invaders, barely making it back to his home dimension. The Teen Titans travel to the water tower, and repeat Walters' prior actions. They, too, are drawn into the alien dimension. The Teen Titans fight a running battle, throughout the school, as they try to elude the aliens' search and destroy squads. In the physics lab, the Teen Titans discover that Downs is really an advance scout for the alien invasion force.
Kid Flash attempts to destroy the dimensional bridging device, but instead merely disrupts it's function. The two dimensions begin to bleed into one another, allowing the aliens to invade the Earth. Robin attempts to evacuate the school, only to find that the faculty and students are being drawn into the aliens' dimension. Fighting another running battle through the school, the Teen Titans double back to the physics lab. There, they find Walters and Downs locked in combat. A stray shot from Downs' weapon destroys the bridging machine, sealing the warp between the two dimensions... with Walters on the other side. Kid Flash races at super-speed, fast enough to pierce the dimensional barrier, and retrieve Walters. With Walters vindicated, the Teen Titans take their leave.