As the overloaded Endeavour reaches the end of its long voyage and its hoped-for planetfall, the refugees from Earth need to find out:
- Can they live on the planet Elpis?
- What threats will it throw at them?
- How quickly can they safely disembark - if they can disembark at all?

Endeavour is desperately needed back on Earth to help rescue the last survivors. But if it does not establish a foothold on Elpis, there will be nowhere for them to go.

Both on Elpis and back on Earth, though, the greatest threat to humanity is still humanity itself.