The Whirligig of Time

The planet Nifron D has been
inexplicably turned into a sun. A quarter of a galaxy away, a native on
the planet Skarnaf has been found horribly disfigured by an impossibly
massive dose of radiation. While Darzek searches for a connection
between the two events, the populous and prosperous world of Vezpro
receives a blackmail letter that threatens it with the fate of Nifron D. 

 In a crimeless society, has a master scientist turned master criminal?
Darzek must decide quickly whether the letter is a monstrous hoax. If it
is not, how can the impossible demands be met -- or five billion
inhabitants evacuated in time?