The Black Arrow is the story of an adolescent hero caught in a confusing world of rapidly shifting loyalties. Following the murder of his father, Sir Harry Shelton, Dick Shelton has been placed under the guardianship of the dubious Sir Daniel Brackley. Sir Daniel is a turncoat, siding with either the Lancastrians or the Yorkists depending on which faction seems to be winning the prolonged conflict. His chief supporters are Sir Oliver Oates and Bennet Hatch.

Dick only gradually realizes that Sir Daniel is capable of great evil. His first hint comes early in the novel when one of Sir Daniel's men is killed by a black arrow bearing the words "John AmendAll." Soon after, a note appears from the mysterious John Amend-All, accusing Sir Oliver of murdering Dick's father and warning that three more black arrows await Sir Daniel, Sir Oliver, and Bennet...