A profoundly bizarre, disquieting work of early speculative fiction.
A man named "Krag" crashes a seance and invites two of the guests, "Maskull" and "Nightspore" on a trip to the planet Tormance, orbiting the binary star Arcturus.
Maskull wakes up in a desert, alone. He has new sense organs on his head and a tentacle protruding from his heart. The landscape is bizarre and psychedelic. There are two new primary colors, and water moves in ways it's not supposed do. Life is malleable -- Maskull sprouts a variety of new organs, most of which open or close various Doors of Perception.
The narrative moves between dyads and triads. Aside from the seance at the start, there are never more than three characters in play at once (it would make an interesting stage play; you'd only need three actors). The characters are archetypes and mouthpieces for philosophical/mystical attitudes. An obscure dialectic unfolds as Maskull encounters them, often ending in sudden and upsetting acts of violence.
