A boy and a bear go to sea, equipped with a suitcase, a comic book, and a ukulele. The bear assures the boy that they are traveling a short distance and it really shouldn't take very long. But then they encounter "unforeseeable anomalies": turbulent stormy seas! a terrifying sea monster! and the rank remains of The Very Last Sandwich. The odds are pitted against the boy and the bear and their boat.

Will the Harriet, their trusted vessel, withstand the violent lashings of the salty waves? And will anyone ever answer their message in a bottle?