Diamond in the Dark

"It was seven months since the world had ended, and it was her birthday"

Endeavour, the Earth's first starship, carrying the refugees from the ruined Earth to the stars, with a murderer on the loose on an ailing starship...

The few survivors on Earth, fighting to survive long enough to be rescued by the under-construction second starship - which will be doomed in any case if Endeavour fails in its mission... The world might have ended, but the struggle to survive has not.