On a planet with six suns, night is about to fall for the first time in two thousand years . . .
The planet Kalgash is on the brink of chaos—but only a handful of people realize it. Kalgash knows only the perpetual light of day; for more than two millennia, some combination of its six suns has lit up the sky. But twilight is now gathering. Soon the suns will set all at one—and the terrifying splendor of Nightfall will call forth a madness that signals the end of civilization