Cat brothers Cecil and Anton are as different in personality as they are in looks. Cecil, stocky and black with white patches, thirsts for seafaring adventure as he roams the docks of his harborside home, taking day trips on fishing boats when the chance comes along. Slim, gray Anton prefers listening to the sailors’ shanties at the town saloon. But one day when Anton does venture to port, he’s stolen off the dock, and the next thing he knows, he’s at sea.

Knowing little of the wide open ocean that lies beyond the harbor, Cecil boards another ship in hopes of finding Anton. But what begins as a rescue mission turns into a pair of high seas adventures, with thrills and danger bubbling under every wave.

Anton takes on a fierce rat, outwits hungry birds, and forges a forbidden friendship, while Cecil encounters dolphins and whales and finds himself in the middle of a pirate raid. On an ocean as vast as the one Anton and Cecil have discovered, will they see home—or each other—ever again?