At the start of the story, True Son, a white boy whom Lenni Lenape Indians captured at age four and later adopted as one of their own, is in turmoil. After eleven years with his Indian family, he is told that he must return to his white family because of a newly signed treaty. True Son fights against going, but his Indian father releases him to an army expedition that includes a guide nicknamed Del, who had once lived among the Indians and spoke their language.
The expedition arrives in Pennsylvania, and True Son meets his white father and learns that his birth name is John Cameron Butler; his white family refers to him as Johnny. True Son/Johnny immediately dislikes his white father, whom he considers small and weak compared to his Indian father, Cuyloga. Johnny's white family is appalled at the Indian ways that he has adopted and tries to get him to return to his white, Christian upbringing. True Son/Johnny distrusts white men, however, and is particularly upset to be among members of the Paxton Boys, a group of men known for massacring Indians. True Son/Johnny tries to run away, but he's caught and returned. The entire time he lives in Paxton, he dreams of returning to his Indian family. The only white person he is able to connect with in any way is his little brother, Gordie.
While recovering from a life-threatening illness, True Son hears his Indian cousin and best friend, Half Arrow, calling to him. Half Arrow has come for him. Unfortunately, Little Crane, who accompanied Half Arrow, has been killed by True Son's white uncle, Wilse Owens, one of the Paxton Boys. True Son and Half Arrow vow revenge, but their plans are thwarted before they can finish killing the man.
The boys return to their Indian home, and True Son receives a warm welcome. However, Little Crane's family is determined to avenge his death and calls for war. Hoping to ambush a boatload of whites, the Indians ask True Son to be a decoy. Posing as a lost white boy, he succeeds in getting the boat to come toward him but is unable to carry through with the plan. Outraged, the Indians hold a trial to determine True Son's fate. True Son's father steps in and spares his son's life, but he banishes True Son from the tribe and his Indian family forever. At the end of the novel, True Son is back where he started, approaching the white side of the forest. There's one important difference however: In the beginning, he had two families willing to fight for him; now, neither family wants him, and his life is in danger in both cultures.