Young Alec Ramsay is shipwrecked on a desert island with a horse destined to play an important part in his life. Following their rescue their adventure continues in America.
Pulled to a desert island by a wild black stallion he has freed during a shipwreck at sea, then rescued by a southbound freighter, a seventeen-year-old boy befriends the horse, trains him by night, and rides him to victory in a match race.