Roger Byam is introduced to the reader, and we learn that he has been extended an invitation by Captain William Bligh to embark on an expedition to Tahiti to gather breadfruit trees and take them to the West Indies, where they will be planted and their fruit fed to the slaves of English colonists. Byam is expected to formulate a dictionary of the Tahitian language.
The Bounty sets sail in November 1787, and its crew is introduced to the reader. The ship makes calls on several islands during its journey to Tahiti, and, meanwhile, conditions aboard the ship begin to deteriorate. Food rots, the crew suspects Bligh of hoarding food for himself, and several men are accused of stealing. Discontent is mounting among the crew.
The Bounty reaches Tahiti, and Byam begins studying the Tahitian language with the aid of some of the natives. Members of the crew begin the task of digging up young breadfruit trees and storing them on board the ship. Many of the men form attachments to the Tahitian women, and the realization that the Bounty will soon be sailing from this idyllic life causes grumbling among the crew. Not surprisingly, three men desert before the ship leaves.
The Bounty sets sail for the West Indies to deliver the trees, and early in the voyage, Bligh harasses his crew — in particular, he accuses some of them of stealing coconuts. His officers, notably Fletcher Christian, begin grumbling over the poor treatment that they are receiving at the hands of Bligh. Accordingly, one morning, some of the crew, led by Christian, seize the ship and force Bligh, along with some of Bligh's followers, into the Bounty's launch to fend for themselves on the high seas. Those who wish to accompany Bligh but cannot because of the already-crowded conditions in the launch are forced to remain with the mutineers aboard the Bounty.
Christian immediately begins sailing the South Sea in search of an uninhabited island, but finding none and tired of the complaints of his fellow mutineers, Christian returns to Tahiti, where he drops off those who wish to stay on the island, including Byam. Then he resumes his search for an unchartered and uninhabited island.
Byam eases himself back into the idyllic life he experienced the first time on the island, and soon he marries a Tahitian princess. A child is born to the couple, and life on Tahiti continues to be a paradise-until an English ship drops anchor at the island. Byam rows out to meet the vessel and is immediately imprisoned as a mutineer, along with the other Englishmen on the island.
While taking the prisoners back to England to be tried for mutiny, the ship runs aground on a reef and sinks, but not before the crew and prisoners have taken refuge in the ship's smaller boats. The small boats make an open-sea journey, and finally, after several months of sailing and torturous conditions, they reach land safely. The mutineers are imprisoned aboard another vessel, which takes them back to England to await their court-martial.
The court-martial of Byam and his companions begins. Testimony is given by the men of the Bounty who made it back to England. Byam and the other men are then allowed to present their defenses. The judges deliberate and find Byam, along with five of the other nine men, guilty of mutiny against the Bounty. Three of the six condemned men are taken to be hanged, and the other three, Byam included, are spared the rope only hours before their seemingly inevitable deaths. Byam is spared because Robert Tinkler, a friend of Byam's aboard the Bounty, corroborates Byam's testimony at the court-martial concerning his innocence, and the other two men are saved from hanging after being pardoned by the proper British authorities.
Byam returns to his family home to live out his life, but is persuaded into duty aboard another ship by the ship's captain. The ship battles the Dutch off the coast of Spain and is victorious.
Byam is promoted to captain, given his own ship, and ordered to sail to the South Sea. While there, he sets anchor at Tahiti, where he learns that his wife is dead, but that their daughter is alive. He meets with Helen, now grown, but does not reveal his identity to her. The novel closes with Byam reviewing the events of his past and contemplating the future.