After his uncle's death, Harry Gilder takes ownership of a ketch, the Bridget B., which he renames the Ina. The ketch is chartered by a man named Jamieson and his colleague Albot, for a trip to Tofumira, 300 miles north of Fiji. Harry invites his friend, Norman, along, intending to 'combine business with pleasure'.
On the journey, Harry discovers onboard a letter from his uncle that outlines a legacy of valuable pearls hidden on the island, of which Jamieson and Albot are aware. A battle ensues for the recovery of the pearls and a safe return to Melbourne.