Is he George Whitley, a twentieth-century writer of science fiction - or Peter Quinn, Second Officer of the interstellar liner Lode Maiden?
An injection of lysergic acid and Whitley finds himself ... where ... who ... and in what age? He is inhabiting the body of Second Officer Quinn but his mind is still that of George Whitley.
Aboard the Lode Maiden he can capture only fragments of Quinn's memory and consciousness, until a magnetic storm throws the ship off trajectory into the deep reaches of space. Then, somehow, enough knowledge comes to him to enable him to help land the ship on an unnamed planet on the Galactic Rim.
But the forced landing damages the ship and kills the Captain, leaving Quinn - or is it Whitley? - to lead the crew and passengers to safety through the horrors and dangers of the unknown planet.