Major Frank McCloud (Humphrey Bogart) travels to Key Largo to see the father, James Temple (Lionel Barrymore) of one of his fallen comrades in war. Temple and his daughter-in-law Nora (Lauren Bacall) run the Hotel Largo where McCloud settles in to pay his respects to his friend's family. Soon, however, a mobster, Johnny Rocco (Edward G. Robinson) and his gang take over the hotel to hold out there until a hurricane passes over the island. Instead of maintaining a quiet co-existence with the occupants of the inn, Rocco delights in torturing them. His girlfriend Gaye Dawn (Claire Trevor) watches as McCloud responds to Rocco with courage. Nora also admires McCloud and lends her own courage to try to overcome the gang. With a struggle of good against evil, surprising twists of loyalty and the fury of nature, these keep the struggle to survive suspenseful until the very end.