Former gladiator Phaedrus is made king of the Horse People, a northern British clan, impersonating Midir, the true Horse Lord whom the wicked queen Liadham blinded and so disabled him from coming to power. Phaedrus and his followers try ridding themselves of Liadham, but she escapes. Many battles against her follow. The Mark of the Horse Lord will draw you into the days of ancient Britain with the adventures of the new king.