A mysterious force has been spreading over the plains of Avantia. There have been sightings of a mysterious horseman, and now one of the farmers has disappeared during an overnight cattle drive. Tom and Elenna speed to the plains to stop Tagus the NightMare before he can do any more damage. But Tom himself is mistaken for the horseman and thrown in jail. Can he win the trust of the people and his own freedom before it's too late?