After being marooned in the South Seas for six years, Bob Randall returns to his home in Faith Harbor, Maine. He discovers that his sweetheart has married Jed Hobbs, a villainous sea captain, and that his mother, dispossessed of her home by Hobbs, has met an early death. Bob vows revenge, finds Hobbs at the village inn, and floors him in a fight. In the company of Jimson Weed, a new-found friend, Bob boards Hobbs's boat, hoping to prove him guilty of smuggling contraband. Bob and Jimson discover a load of guns and gunpowder bound for Central America and capture the members of the crew one by one. Hobbs at first eludes capture, but when he is cornered by Bob, he drops a lighted match into the powder hold. The ship is destroyed in the resulting explosion, but Hobbs alone is killed. Bob is then reunited with his former sweetheart, who is now free to marry him.