Phillip, a young boy traveling away from war with his mother, is on a ship headed for America when it is torpedoed. When he wakes up he finds that he is on a rescue raft with a black man named Timothy and Stew Cat (the cook's cat). Timothy is well versed in survival and helps the three get to an island safely.
Phillip goes blind three days after the ship wreck and Timothy is all he has. It takes Phillip's blindness to see past Timothy's skin color and let him impact his life. The three remain on the island, surviving and hoping for rescue, all the while becoming friends.
See the enotes link for a more complete summary of the book.