A monk named Brother Luke rescues Robin and takes him to the hospice of St. Mark's where he is taught woodcarving and--much harder--patience and strength. Says Brother Luke, "Thou hast only to follow the wall far enough and there will be a door in it."
Robin soon enough learns what Brother Luke means. And when the great castle of Lindsay is in danger, it is Robin, who cannot mount a horse and ride to battle, who saves the townspeople and discovers there is more than one way to serve his king..
Buy The Door in the Wall by Marguerite de Angeli from Australia's Online Independent Bookstore, BooksDirect.