The opening few chapters.
It’s 2169 and a new Ice Age threatens civilisation. Ex-commodore Bonar Hall will provide the computer power for a twelve-year emigration to 18 Scorpii. Not everyone wants him to go: he has an expensive past.
But Flight Pilot Heather Barnard is going. So too among the colonists is former model Aurora Nova. Bonar owes Heather; he doesn't know Aurora, yet.
All this may not matter if the emigration fleet doesn't make it, and history is not on their side.