David, a college-aged sea biologist dives into the sea after findings strange radio frequencies of a possible human-like civilziation in the sea. There he visits Bikini Bottom, but this place is not the whimsical comedic one. David and a group of other sea divers are terrorized by a mutanted and bloodthristy talking Sponge and his friends and must find a way to escape back to the surface before they all drown in red.
