Richard Devine is a British aristocrat. The son of wealthy ship-building magnate - or so it is thought - Richard's life changes when his mother reveals to his father during an episode of domestic abuse that Richard is not his son. Lord Bellasis is Richard's biological father. Devine Senior threatens to ruin the reputation of Richard's mother if she does not banish her son from their house immediately. He then goes to find his lawyer so that he can change his will and disinherit Richard. Richard packs his belongings and leaves, but shortly after he has left the house he discovers the body of Lord Bellasis, and sees Sir Richard hurrying away from the scene. The police find Richard with the body and arrest him, believing him to be the murderer whom they have caught red-handed. He gives his name as Rufus Dawes. Because of a complete lack of evidence Rufus is acquitted of the murder, but is found guilty of robbing a corpse, and sentenced to transportation to the penal colony of Australia.
Dawes is transported to Van Diemen's Land in 1827 aboard the Malabar, which is also carrying one Captain Vickers, ironically the newly-appointed captain of the penal settlement in Macquarie Harbor, where Dawes is headed as well. Vickers' wife and daughter are also traveling with him, along with Sarah Purfoy, his wife's maid. Sarah has come aboard with one objective; freeing her lover John Rex, who has also been sentenced to transportation. She organizes a mutiny on the boat with the help of three other passenger, whilst John Rex is hospitalized on board with a fever. Dawes overhears their plan and warns Captain Vickers who takes the precaution of doubling up on the guards. The mutiny is thwarted but John Rex discovers that Dawes alerted Vickers. He claims that it was Dawes himself who was the ringleader, for which he is found guilty and given a life sentence.
It is now 1883, and at Macquarie Harbor Lieutenant Maurice Frere, Dawes' cousin, informs Vickers that the settlement there is to be closed and amalgamated with the settlement at Port Arthur. Dawes already knows who Frere is, having recognized him as his cousin, and the day that Frere brings this news to Vickers, Dawes is in solitary confinement, having proven himself to be something of a problem prisoner. He has had several attempts made on his life by the other prisoners who view him as a "squealer" and he has made several unsuccessful escape attempts. Believing that death is preferable to being governed by his cruel cousin he attempts to kill himself.
It is decided that Captain Vickers shall go on ahead to Port Arthur with the majority of the convicts. Frere will follow on another ship, with Vickers' wife and daughter, and ten remaining convicts, including John Rex, who is again plotting a mutiny at sea. This time he is more successful. The mutineers take over the ship and killing several of the soldier guards. Rex, Vickers and Frere are marooned.
Dawes manages to swim towards the intended encampment at Port Arthur and discovers the tiny shipwrecked community. They are wary of him at first but soon discover that they are able to trust him and that he is actually very useful to them as he is a skilled survivalist and consequently makes their lives much easier. Sylvia, Vickers' daughter, likes him, which makes Frere jealous and angry since he has been trying to win her affections for quite some time without any success at all. Frere has promised that Dawes will be pardoned but still continues to bully him and treat him as a slave, which so demoralizes Dawes that he thinks about leaving before he is pardoned. Eventually the entire group takes to the ocean again, primarily because Mrs Vickers is gravely ill and Sylvia is becoming sick as well. They are found drifting by an American vessel and rescued.
Port Arthur, 1838. Following the death of her mother and her own amnesia brought on by illness, Sylvia is engaged to Frere, who has told her the story of the mutiny as he would have liked it to have been, with himself as the courageous hero who saved her life, and with Dawes as a savage criminal who attempted to murder them all. The original mutineers are captured and their trials scheduled. Sarah Purfoy begs Frere to speak on behalf of John Rex, threatening to expose him as a philanderer and a liar to Sylvia if her refuses. Of course he complies with her request. Dawes is also brought in from Hobart to identify the men and confirm that they were indeed the mutineers. He is surprised to see Sylvia because he has been told that she had died. He is prevented from speaking to her when he tries. The mutineers escape the death sentence and are sentence to life imprisonment instead. He escapes from Hobart shortly afterwards in order to try to speak with her again but because of her amnesia she believes what Frere has told her about Dawes, and is terrified of him. Her screams for help paralyze him and so he is captured immediately and returned to the Hobart encampment. He is ordered to flog a fellow prisoner but refuses, and is punished for this disobedience by being flogged himself.
Despite their former enmity, John Rex approaches Dawes to aid and participate in another escape attempt. Initially refusing, Dawes learns from Rex that he had been employed by the Devines to find their only son. He asks if he would still recognize the man he had been sent to find; Rex admits he likely would not. Rex devises a second plan when a warder casually remarks that the two men bear a striking resemblance to each other. A few days later he and another group of prisoners escape. However, they get lost in the Tasmanian bush and are driven to madness, eating each other when there is no other food. Rex continues on without them, but tires quickly of Sarah, escapes to London, and presents himself as the long lost Devine son. Without her husband to threaten her honor, Lady Elinor Devine (Dawes' mother) accepts him back.
By 1846, Frere is installed as the new Commandant of the Norfolk Island settlement and he brings with him a new and sickening brutality. He also wants nothing more than to break Dawes' spirit, which he finally succeeds in doing. Dawes and two other men who are similarly broken draw lots to allocate roles in their plan to escape this brutality by death. They murder one, and the remaining two, Dawes included, are sentenced to death for his murder. Reverend James North, erswhile friend of Dawes, hands in his resignation as Chaplain because he can no longer bear witness to the brutality meted out by Frere. He has also fallen hopelessly in love with Sylvia. He promises to tell Sylvia the true version of the story of the mutiny, because she is starting to suspect there is much more to Dawes than the things she has been told. He does not do this because of his love for her. Seeing Dawes on a stretcher after his sentencing, she orders his release, which angers Frere and cements her decision to return to her father, and leave her husband.
In London, Sarah has finally caught up with John Rex who is living the high life and bringing shame to his mother. She threatens to tell Lady Elinor his true identity if he does not introduce her as his wife. Lady Elinor is already suspicious of Rex and decides to call his bluff by telling him that he cannot sell the family home since he has no entitlement to it. As the bastard son of Lord Bellasis he was disinherited by her husband before his death. Rex suddenly realizes why there is such a strong resemblance between himself and Dawes; he too is the illegitimate son of Lord Bellasis who had a brief sexual relationship with Rex's mother when she was a maid in his house. He confesses to the murder of Lord Bellasis, who laughed at him when he told him his story. Lady Elinor tells Sarah that she will allow them to leave the country on one condition - they give her news of her real son.
Before Reverend North leaves Norfolk Island, he visits Dawes and tells him that he never talked to Sylvia because he is in love with her himself. He also confesses that it was he who robbed the corpse of Lord Bellasis because he was trying to find the proof that Bellasis had of his forging bank notes. When North leaves, he is flustered and confused, and carelessly leaves behind his hat and cloak. Dawes seizes the opportunity to escape and embarks the boat leaving for Port Arthur disguised as the Reverend when the drunk prison warder forgets to lock his cell after North's visit. He finds Sylvia, who remembers the man she had known before her amnesia. The boat is caught in a terrible storm and the following morning, the bodies of Dawes and Sylvia are found entangled together, floating on a piece of wood from the sunken ship.
