Based on Rudyard Kipling's novel, a spoiled rich boy falls off a cruise ship and is taught about life by a Portuguese sailor on a fishing vessel.
Harvey Cheyne (Freddie Bartholomew) orders breakfast in bed for his friends. He gives Charles (Bill Burrud) a valuable book and tells him to let him into their club or his father will fire Charles' father. Charles tells his teacher Tyler (Donald Briggs) about Harvey's threat. Harvey left $50 for Tyler, and for bribing he is sent to Coventry, meaning no conversation with him. Harvey speaks and is knocked down. He leaves school and tells his father Cheyne (Melvyn Douglas) that Tyler took a bribe. Cheyne learns that Harvey is suspended and takes him on a cruise. Harvey makes the soda fountain open early and stuffs himself.
Harvey falls into the ocean and is picked up by Manuel (Spencer Tracy). On the fishing vessel Harvey tells Captain Disko Troop (Lionel Barrymore) his father will give them money. Disko's son Dan Troop (Mickey Rooney) gives Harvey clothes. Disko tells Harvey it will be three months and gives him a job. When Harvey threatens them with jail, Disko hits him. Harvey refuses to work for food. Long Jack (John Carradine) says a passenger is bad luck. Manuel is asked to make Harvey work. Harvey tries to fight Manuel, who makes him toss one fish so he can eat. Manuel sings and tells Harvey about the sailor's angel. Manuel makes up songs. Disko yells at the rival ship of Cushman (Oscar O'Shea).
Harvey wakes on deck with Manuel's coat; he thanks Manuel for saving his life. Men chop bait and sing, but Manuel sends Harvey below to haul slop. Dan tells Harvey that Manuel fishes alone since his father died. Harvey tells Manuel what he learned in a book. Jack still calls Harvey a Jonah. Manuel bets Jack his razor and takes Harvey fishing. Harvey asks Manuel how his father died, and Harvey describes how they fish in heaven. Harvey catches a halibut and tells Manuel that he tangled up Jack's trawler. Manuel throws the halibut back and takes Harvey back to the ship. Manuel pays the razor to Jack, who got hooks in his arm. Harvey admits he did it, and Manuel protects him from Jack. Harvey tells Manuel that he is ashamed, and Manuel sings.
They fish the Grand Banks. Disko rings the bell he has a full load and races Cushman back to Gloucester. Harvey bravely asks Manuel to remove a hook from his hand. Manuel tells Harvey what he will buy and do. Harvey doesn't want to go home. Disko and Cushman take risks, and their ships almost collide. A mast breaks; Manuel loses his legs, says good-bye to Harvey, and drowns. At port Jack gives Harvey the razor, and Disko gives him Manuel's hurdy-gurdy. Harvey asks to fish again. Cheyne learns of Manuel from Disko. Harvey donates candle-sticks for Manuel at church and prays, as his father listens. In the boat Harvey cries, and his father tries to console him. In the final scene they attend a memorial service for sailors lost at sea.
This classic story portrays the maturing of a spoiled kid by hard work at sea with a simple but spiritual fisherman, while his wealthy father learns what he missed by not teaching his son responsibility. Sadly, the useless competition between the ship captains results in the death of the friendly Manuel.