After World War II, bar pilot Johnny Duval returns home to Louisiana after serving in the Coast Guard. Johnny has unsteady nerves after being responsible for a wartime shipwreck in which many men's lives were lost. While Johnny was away, a Cajun named Mike Kalavich courted his sweetheart, Toni. On his way, Johnny meets Janet Hilton, a wealthy society girl, who is immediately impressed with his rugged manliness. Johnny's old captain, Pierre Moise, is eager to rehire Johnny, who used to be his top bar pilot, but Johnny refuses to accept the job. A pilot friend of Johnny fakes an illness in order to get him to pilot Janet's father's yacht in the fog. Johnny successfully steers the boat to safety, and his commission as lieutenant in the Coast Guard Reserve is restored. At a town dance, Mike picks a fight with Johnny, but he refuses to fight back. Toni willingly fights Janet, however, who now rivals Toni for Johnny's affections. The night before Johnny and Toni are to marry, he is called to rescue a ship in the fog and rams into a boat, killing Toni's brother Tim. After the funeral, Johnny turns to drink and is injured in a traffic accident. He lies unidentified for weeks in a charity hospital; finally, Janet has him moved to her house to take care of him. When Toni and Captain Moise visit the Hiltons, she upbraids them for forcing Johnny to be a bar pilot and refuses to let them see him. After Johnny recovers, Janet gets him a job with Hilton, who now owns the formerly free lands of the bayous where the locals hunt, fish and trap for their livelihood. Mike, who is a trapper, disdainfully disregards Hilton's posted warning signs. One day, Johnny and Janet catch Toni illegally hunting and accidentally hit her canoe with their motorboat. Toni is thrown from her boat, and Johnny wrestles an alligator to save her. Later,Janet and Johnny hear a shot, and Johnny discovers that Mike and his friend Alex were trying to run a trap and were fired upon. Alex accuses Johnny of complicity with the Hiltons in breaking the tradition of bayou rights and tells him that every effort Toni made to see him was thwarted by Janet. Johnny confronts Janet, and she admits she intercepted Toni's letters and calls. After unsuccessfully trying to incite a riot among the trappers, Mike starts a swamp fire, and Toni races to the island to warn Johnny. As the fire spreads, Johnny and Toni call for each other, but when they finally embrace, Mike shoots Toni. Johnny knocks out Mike then rescues him and Toni from the engulfing flames. Later, Toni recovers and Johnny pilots a tanker for Captain Moise.