Dr. Rico Symes is testing out his new weapon, a half-pterodactyl, half-barracuda known as the Pteracuda, hoping to sell it to the military. But when the test goes horribly wrong, his monster goes off on a killing spree. Symes and his head of security, Hamm, realize there is only one way to stop the Pteracuda's rampage, with another monster. They head to a marine institute that is keeping the creature known as Sharktopus. The two beasts engage in a brutal battle, in which only one will survive.