After years of being strictly house cats, Marco and Polo escape into the wonderful, but dangerous outside world and are sent on three challenging adventures by a group of cats known as the Club of Mysteries.

Polo finds his mother and tries to impress her with his courage as he and the other members of the Club of Mysteries set out on new adventures. Polohas always longed to find his mother. All he remembers is that she was soft and warm and smelled of milk. So when sassy, street-smart Geraldine returns, she isn't exactly the mother he expected. But Polo is still thrilled to have found her and is eager to show her off to his pack of friends in the Club...

The Hooligans sneak along when Roxie Warbler goes on a beach vacation with her beloved Uncle Dangerfoot, and soon they uncover the secret invention he has been hiding from his nemesis, Alfred Applejack.

"Continues the adventures of Marco, Polo, and other members of the Club of Mysteries as they care for Carlotta's kittens and search for a home for them."