The generation ship the 'Peerless' is suffering from a population explosion, and the only way to reduce the number of children is by drastically limiting the females' food intake, which will trigger a natural response to famine and stop procreation. So population control consists of two barbaric choices: starvation, or suicide. Trying to find a better way, a biologist starts experimenting with animals, and stumbles on a technique that radically alters the reproductive cycle. But while the advantages are obvious, there's a major drawback: while it spares women from their old role - reproduction without hope of survival - it will essentially wipe out an entire sex. Amid the turmoil created by this new possibility, physicists on the ship are working to develop the technology they will need to complete the mission of the 'Peerless'. The people who brought the ship onto its present orthogonal trajectory used up so much fuel that there is no hope of returning -- unless they can use what little remains far more efficiently. One of the expedition's founders dreamed of discovering the Eternal Flame: a way to generate thrust without consuming any fuel at all.
The inhabitants on board the 'Peerless' have some hard choices to make -- and the wrong one could spell extinction for their entire race!