Under The Trailingsword Gil MacDonald, soldier and exile in an alternate reality, must find Yardiff Bey, master wizard and archvillain. Bey has abducted Gil's friend and threatens to destroy this world of mystery and magic that the American has made his home. Coramonde's Prince Springbuck sends him south to the accursed lands of Shardishku-Salama, where Yardiff Bey waits to capture and torture him.
With the comet Trailingsword hanging in the sky above, Springbuck sets out with his army to save Gil from an enemy that cannot be slain.