Hammerfall
C.J. Cherryh
The fate of an interstellar empire rests on one man: a prince and warrior
named Marak. Marak has always hidden his "madness" -- voices and visions
that beckon him toward a silver tower. When betrayal brings him
face-to-face with the dictator of his world, the mysterious Ila, Marak is
assigned a seemingly suicidal mission to cross his planet's vast desert to
find that tower.
This summary is courtesy of McNaughton Books