The animated portions of the show focused on a canine private investigator named Ace Hart. The Muppet portions of the show focused on the interactions between Ace Hart and his animator Eliot Shag (who, like Ace, is a German Shepherd). Eliot would illustrate the stories while Ace would go traverse through it, occasionally breaking the fourth wall to speak with Eliot about the various troubles with the story. In one episode, Eliot even enters Dog City himself to join Ace in solving a mystery.