The citizens of Acmetropolis are celebrating the Loonatics on the one-year anniversary of the meteor strike, when the sky is suddenly filled with pieces of rock falling from the stars.

Mallory Mastermind, Sypher, Weathervane, and Massive have been unwillingly recruited by a mysterious alien being known as Optimatus.

The Loonatics encounter Adolpho, a mutated dolphin who uses psychic abilities to brainwash sea creatures and destroy any human-made object at sea. It's up to the Loonatics to stop Adolpho and his gang of killer dolphins from taking revenge on the "surface-dwellers" at their next target: Acmetropolis.