The Castles of Athlin and Dunbayne by Ann Radcliffe, Fiction, Action & Adventure

Years ago, when Young Earl Osbert of Castle Athlin was a boy, his father was ambused and slain by Baron Malcolm of Dunbayne. Now Osbert has come into his majority, and in the company of a sturdy and heroic young peasant named Alleyn he's gone to avenge his father's murder. What waits for them at the castle of Dunbayne is not vengeance but a fate that neither one of them imagines: not just conquest or defeat, but a terrible chanllege -- and the romance of a lifetime. (Jacketless library hardcover.)