Just off the South Sea island of Haleakoloha, World War II hero "Boats" Gilhooley jumps ship and swims ashore in search of his Navy buddy, "Guns" Donovan. Each year on their birthdays (December 7), the two men engage in a barroom brawl; this year's ritual takes place in Donovan's Reef, a tavern owned by Guns. The men nearly destroy the place before the fight is halted by island physician Doc Dedham, the third member of the naval trio. Meanwhile, Dedham's daughter, Amelia, is on her way to Haleakoloha from Boston, hoping to prevent her father, whom she has never seen, from inheriting a huge family fortune. When the three friends learn of the visit, they arrange for Guns to temporarily adopt the doctor's three halfcaste children, assuming that Amelia would never accept them as brothers and sisters, even though their late mother was an island princess. Their fears about Amelia are well-founded; although she likes the children, her relationship with Guns and Gilhooley is stormy. Island governor André de Lage attempts to court Amelia--largely for her money--but he is rebuffed. When she defeats Guns in a swimming race after a water-skiing expedition, she begins to enjoy his company. Then she learns that the children belong to her father, blames Guns for depriving them of their natural home, and walks out on him. Reconciliation attempts are interrupted when Guns and Gilhooley take on a barroom full of Australian sailors in a huge free-for-all. In the end, Amelia decides to marry Guns and remain on Haleakoloha; Gilhooley finally agrees to marry his longtime girl friend, Fleur; and a business transaction between the two brawling buddies turns the tavern into Gilhooley's Reef.