A sponge diver hopes to make enough money to buy his own boat and marry his girlfriend. A rival diver, however, has other plans for him.
Although her alcoholic father has arranged for her to marry Savanis, the wealthy but crooked business leader of her fishing village, Rosie becomes engaged to Joe Bethel, an earnest but poor sponge fisherman. To assure Rosie's financial future, Joe decides to buy a new fishing boat, but because his family's boat has been declared "jinxed" by the superstitious villagers, he is unable to raise enough money for the purchase. Savanis, seeing an opportunity to ruin his rival, offers Joe a generous loan and helps him to buy the most modern boat in the area. Confident that he will bring in enough goods to pay off his debt at auction, Joe sets sail with the other boats for the annual sponge run, unaware that Savanis has hired Nick, one of his crewmen, to sabotage the trip. At sea, Nick destroys the boat's anchor and twice meddles with the underwater air pump, which nearly costs Joe and another diver their lives. Back on shore, Rosie learns about Joe's troubles from another fisherman and, by pretending to be bored with her romance with Joe, tricks Savanis into revealing his plot. While Rosie rushes to find Joe in Savanis' speedboat, Joe fights with Nick and forces him to dive. After Rosie boards Joe's boat and identifies Nick as the saboteur, Nick becomes entangled in his sponge bag, and his air hose becomes wedged under a rock, cutting off his air supply. In spite of his anger, Joe risks his own life and dives to save Nick from drowning. When the boat's engine then breaks down, Rosie speeds to Waikiki to get the necessary replacement parts so that Joe can make repairs in time to reach the auction. Before they leave in the repaired boat, however, Savanis' henchmen descend on the crew, and a fierce fight ensues. After Joe, Rosie and a repentant Nick defeat Savanis' men, Rosie takes off in the speedboat to stall the auction. Aided by the sympathetic auctioneer, Rosie defies Savanis and stalls the bidding long enough to assure Joe of his deserved profits. Joe then reveals Savanis' subterfuge to his fellow fishermen and, with Rosie at his side, happily collects his earnings.
