The Brass Dragon — Marion Zimmer Bradley

Barry Cowan woke up screaming in a hospital room with a nightmare where his memory should have been, and a curious brass figurine in his pocket that made the nightmare seem all too likely to be true. Yet for all the emptiness there was a familiarity about the
Stranger who appeared, claiming to be his father -- a HORRIFYING familiarity, tied somehow to the dreams of another world that invaded his sleep. Where had he been? What had happened to shock his mind so deeply that it refused to remember? Unknown to Barry, his deeper self had been wise in forgetting: if his efforts to call back the lost year of his life should succeed, would he survive?