When the Probyn boys, Adolphus and Constantine, come to live with the Roby family, conflict ensues. The Roby children are shocked by Adolphus' and Constantine's behavior. 'How can those boys be so selfish, rude, and spoiled?' the Roby children ask. But in time, the Roby children begin to see their own faults as well. Through allegorical tales of 'Fides the Giant Killer,' told by Mrs. Roby, the children discover that it is not just the Probyns who need to repent and believe in Jesus. The Roby children have their own battle with sin. The giants of Pride, Sloth, Selfishness, Anger, and Untruth in their own hearts must be put to death. Charlotte Maria Tucker's (1821-1893) delightful and creative tale uses allegory to teach children that it is by faith that we overcome the giants of sin. It is by faith in Christ our Captain and Victor, that we overcome. 'This is the victory that has overcome the world—our faith' (1 John 5:4).