When their home is infested by eldritch terror, Rick Sanchez and the Smith family traverse a Lovecraftian hellscape to track down and defeat the big guy himself: CTHULHU.

On their journey through Arkham and the realms beyond, they're waylaid by literary monstrosities and the characters obsessed with them—fighting off hordes of fish-people, finding and losing love, battling sentient cosmic color, and taking potshots at ol' HP along the way.