The Black Unicorn
by Terry Brooks
Book 2 in the Magic Kingdom of Landover series (1987)
Publisher: Del Rey
A year had passed since Ben Holiday bought the Magic Kingdom from the wizard, Meeks. But unbeknownst to him, he has been the victim of a trap by Meeks, who has succeeded in stealing the Paladin and appropriating his face.
Suddenly none of Ben’s friends know him, but all of his enemies do. He must win it all back again–only this time on his own!