Errol Flynn dives into danger in this hard-boiled South Seas adventure directed by action veteran Gordon Douglas and co-starring Ruth Roman and Raymond Burr. When his partner's bumped off after bragging of treasure, salvage diver Gregory Mason (Flynn) sets out to make a killing of his own. The only one who knows where it's buried, Mason's scheme to recover the loot is dashed when a mysterious fire torches his ship. Coming to the rescue, however, is Brock Benedict (Burr), a sinister collector who offers his boat in exchange for a share. Charting a course into perilous waters, a wary Mason makes plans to recover the treasure, while the treacherous Benedict prepares to deep-six his new partner and keep the fortune all to himself.