On his first morning at sea, ship's cat Trim looks for ways to help out, and makes a new friend along the way.

Trim has learned a lot about life at sea. He understands the daily routines and the responsibilities of each crew member, and he knows many of the ways to help. But one day he ventures outside and experiences something new and scary: a storm is brewing. As the wind whips his whiskers and the sky grows dark, Trim's heart beats like a drum. All his friends are doing new things: preparing the sails, closing any openings on deck, and securing loose items....