James Beale, an evil archeologist, along with Captain Morse Damon, has setup
an expedition in search of the Black Planet that is supposed to exist beyond
the orbit of Pluto. A planet that is not actually black but invisible, covered
as it is in an artificial "negasphere"; it doesn't occlude any starfield. On
Mars, they'll force the spaceman Nils Esterling to go with them.
The Black Planet is the world of winged people - men & women who fly, the
"Valkyries" of the (Norse?) legend. People who once had advanced technology
that's now forgotten. A world that once revolved around another sun, but was
moved as a ship by its inhabitants to escape a war, & finally parked on the
outskirts of Sol.
Here Nils will find his own roots & his lady love. And their tragic end that
will leave them wingless & earth bound, after he's forced to kill the two
crooks.