C. J. Cherryh

Marak, a mad prince whose life is devoted to overthrowing the Ila, his world's eternal dictator, is betrayed by his father and sent on a march with other madmen to the Ila's city of Oburan--and, upon arrival, the Ila assigns him to discover the source of the visions and voices that haunt his world's madmen.

Guil Stuart and his telepathic nighthorse ride out to find the rogue horse that killed Guil's lover Aby, and is terrorizing the mountain villages, but there are others on the dangerous trail, some who would help and others whose intentions are not so honorable.

Danny Fisher and his telepathic nighthorse Cloud rescue three children from Tarmin, a village destroyed by a vermin swarm, and take them to the mountaintop town of Evergreen where they are greeted with a mixture of sympathy and greed from people who are anxious to loot Tarmin's property.