Sea captain Charles S. Chinnough, popularly known as "Captain China," awakens from a drunken stupor and finds that his crew has locked him in his cabin during a typhoon and abandoned ship. China is rescued after the ship is wrecked on a reef, but by the time he returns to civilization, he finds that he has been dismissed, as his first officer, Brendensen, has falsely testified before a board of inquiry that he was responsible for the change in course which resulted in the loss of the ship. Determined to set the record straight, China books passage on a ship commanded by Brendensen. Many of China's former crew members are also aboard the ship, including Geech and Red Lynch, who were responsible for locking him in his cabin. Among the passengers aboard ship are Kim Mitchell, a beautiful woman sailing to meet her home-town fiancé; the Haasvelts, an elderly Dutch couple; and eccentric mystery writer Miss Endicott. During a confrontation with China, Brendensen denies that his testimony was false, but does admit to capitalizing on his heroism in order to get his captaincy. China then confronts Lynch, and they become embroiled in a violent fight and are pulled apart only after Brendensen's officer Alberts is injured and Brendensen draws his gun. Kim is impressed by China's determination and strength, and befriends him even though Brendensen has been flirting with her. When the sea gets rough, China admits to Kim that his fiancée died of a broken heart because of his all-consuming devotion to the sea, and after learning of her death, he became a drunkard. Kim later turns on China because she believes that he is using her to get to Brendensen. When China and first mate Keegan advise Brendensen that a typhoon is brewing, Brendensen ignores them until the storm is almost upon them. Brendensen then adjusts course, but his mishandling of the situation puts the ship in grave danger, and he is forced to humble himself and ask China to take command. China agrees to help only after Brendensen admits he made an error in his calculations. China also helps Trask, a sailor who has lost his confidence and taken to drink, by enlisting him in the recovery operation. When a huge piece of machinery in the cargo deck loosens and threatens to crash through the hull, China goes below to help secure the cargo. Geech and Lynch attempt to kill him by loosening a fastened cable, but the plan backfires and Lynch is killed. By morning, the storm is still strong but they have survived the worst of it. Brendensen confesses that his false testimony cost China his job, but promises that he will now clear his reputation. China professes his love for Kim, but she is convinced that his first love is the sea, and rejects him in favor of her staid and conventional childhood sweetheart, who awaits her in Manila. When the ship docks, however, Kim has a change of heart and runs from her fiancé into China's arms.