A merchant ship's frantic S.O.S. sends the U.S.S. Enterprise^TM speeding to the rescue. But the starships mission of mercy becomes a desperate struggle for survival against a nightmarish enemy Captain Kirk can neither identify nor understand, an enemy he must defeat without the aid of one of his most trusted officers.

Leonard McCoy is a stranger, a man with no memory of his Starfleet career, his family, his friends, or the one thing James T. Kirk needs most of all, his dreams.