In Queensland, Australia in the mid-1800s, three children of Commonwealth settlers are playing in a clearing when a strange man appears, sitting balanced upon a fence. Lachlan, the young boy, sees the man’s darkened skin and assumes he is one of the Aboriginal tribesmen who live in the Australian wilderness. However, after taking the man captive by pretending a long stick is actually a rifle, Lachlan and his cousins, Janet and Meg, discover that the man is in fact a European, though he speaks and acts like an indigenous person. They march him back to the settlement, Lachlan’s ego swelling with an image of himself as a powerful dominator, and show the other white settlers. The settlers are mostly disturbed by the man, who calls himself Gemmy. Though Gemmy is only slowly recovering his grasp of English, Mr. Frazer, the town’s minister and botanist, spends an afternoon interviewing Gemmy and taking his story down as best he can. Gemmy is fascinated by the pages Mr. Frazer writes, believing that they hold some part of himself in them, but Frazer locks them away for safekeeping in the schoolhouse.
16 years earlier, 13-year-old Gemmy washes up on the Australian shore, nearly dead and unsure of where he is. A wandering group of Aboriginal Australians finds him and allows him to join their group and live amongst them, though because of his light complexion they never fully accept him as one of their own. Even so, Gemmy learns the Aboriginal people’s language and customs—forgetting his own in the process, along with his former identity—but some part of him longs for a world he cannot quite remember. So when Gemmy eventually hears that other white people have been spotted settling along the coast, he ventures to meet them.
Back in the settlement, the McIvor family—which includes Lachlan (a cousin), Janet, and Meg along with the girls’ mother Ellen and their father Jock—takes Gemmy in and lets him live on their property, sleeping in a lean-to next to their shack. Although the other settlers are still nervous about Gemmy, since he reminds them of the Aboriginal people and brings to mind their fears of invasion and attack, Gemmy is good with the children and helps the McIvors with what chores he can understand. When he is not working, he follows Lachlan around.
Although Janet had once looked forward to her cousin Lachlan’s arrival from Scotland, now that he has lived with the family for a few years she resents his presence. She is annoyed by his insistence that she always yield or defer to him because she is a girl, even though she is both older and tougher than he is.
The settlers continue to resent Gemmy, and some even think that they should organize a raiding party to kill all the Aboriginal Australians in the area. However, Mr. Frazer enjoys Gemmy’s presence, spending hours learning from the knowledge of plants and herbs that the indigenous people passed on to him. Jock, the father of the McIvor family, wants to set his fellow settlers’ minds at ease, but he is too wary of affecting their good faith in him or risking his social standing. However, Jock’s wife Ellen does not care what others think. She supports Gemmy and proves to be the true strength behind the McIvor family, keeping their lives moving even when Jock is beset by gloom.
After Gemmy has lived with the McIvors for almost a year, he is visited by two Aboriginal men in the middle of the afternoon, who speak with him for a few minutes and then leave. However, the men were spotted by a farmhand, who embellishes the story—claiming that Gemmy was given some kind of mystical stone—and whips the settlers up into a fearful frenzy. Jock defends Gemmy, opposing his neighboring settlers and earning the ire of his community. Although the settlers begin harassing the McIvor family—killing their geese in the night, smearing feces on their shed—Jock and Ellen grow closer together in the midst of their hardship. However, one night Gemmy is kidnapped by the other settlers. They put a bag over his head, beat him up, and hold his head underwater until Jock, who has heard the commotion, arrives and ends it. The attackers flee into the night, and Jock brings Gemmy back to the house and holds him tightly for several hours to comfort him.
As Mr. Frazer is writing his magnum opus on Australian farming and foraging, using the knowledge he gleaned from Gemmy, he learns that Gemmy has been taken to live with Mrs. Hutchence, an older woman who owns a large house farther removed from the settlement, where Gemmy will be safer. Janet begins spending time with Mrs. Hutchence as well, learning about bee-keeping from her. One afternoon, as they are tending the hives together, the bees swarm out of the hive and cover Janet. Although the bees would have stung her to death if she had panicked, Janet remains completely tranquil and still in the belief that the bees will not harm her. The bees eventually dissipate, and though Mrs. Hutchence is mortified, Janet is calm and collected, feeling as if she has just been reborn and received a “new self” who is confident and assured.
Although Gemmy is safe in Mrs. Hutchence’s house, he hates being in such a confined space. The claustrophobia brings back long-forgotten memories about his childhood living with a drunken rat-catcher named Willet. Although Willet often abuses Gemmy and treats him almost like a slave, Gemmy feels an attachment to him since he is the family and source of identity Gemmy has, since he is “Willet’s boy.” However, one night after Willet passes out drunk, Gemmy lights the room they live in on fire in an act of repressed rage. When the fire gets out of hand, Gemmy flees through the window, running until he tumbles into a ship and loses consciousness. Gemmy spends the next two or three years living on ships, hopping from one to the other, until one crew finally tires of him and tosses him overboard, leaving him to drift at sea until he washes up on the Australian coast. Recollecting himself back in Mrs. Hutchence’s room, Gemmy realizes that he desperately misses living with the McIvors, even though he often sees Janet.
Although Gemmy once loyally followed Lachlan around, as Lachlan gets older he feels the need to push Gemmy away. Lachlan is growing, but with age comes the grim realization that the world does not revolve around him and that there are many things he will never understand. Seeing Jock betrayed by his own trusted neighbors for protecting Gemmy leaves both Lachlan and Jock disillusioned and fearful of the wickedness they now recognize in the world.
Mr. Frazer travels to Brisbane to meet the regional governor and present his ideas about botany, suggesting a plan for utilizing the natural food sources of the Australian wilderness rather than attempting to cultivate European crops. However, he is unsuccessful, and becomes disillusioned when he realizes that the governor is a useless fool with delusions of grandeur. Meanwhile, Gemmy goes to the schoolhouse to retrieve what he believes are the pages that Mr. Frazer wrote about his life, but in fact they are only lesson sheets. Even so, Gemmy takes them and marches away into the forest, never to be seen again. As he does, the rain pours and dissolves the written sheets in his hands.
Many years later, Lachlan, now an older adult and a politician, visits Janet at her convent, where she is a nun and a masterful bee-keeper and researcher. They have recently begun meeting after an incriminating private letter between them (which seemed to express pro-German sympathies during the anti-German sentiment of World War I) was stolen from Lachlan’s house and leaked to the press. The event caused an uproar, embarrassing Lachlan’s government and enraging many members of Janet’s community. As a result, other members of the government are calling for Lachlan’s resignation, and the children Janet previously tutored in bee-keeping are forbidden by their parents from visiting the convent. Despite the fallout, both Janet and Lachlan take the events in stride, determined to ride them out. As they sit together, Janet reflects that their family had loved Gemmy, even if they didn’t realize it at the time. Years after Gemmy disappeared, the McIvor family heard a rumor that Gemmy, living with a group of Aboriginal Australians, was killed in a raid by white settlers. Lachlan eventually manages to track down the bones he suspects are Gemmy’s, and though he knows they may not be, decides to believe they are so he can lay his guilt and sadness to rest with the bones.