'Absolution Gap' picks up the story of the survivors of Redemption Ark not long after their arrival on the planet Ararat. Nevil Clavain, once known as the Butcher of Tharsis, now a tragic, heroic figure fully fleshed out in the previous novel, has done a runner from the society he helped to create. He's left Scorpio, an uplifted pig from Chasm City (both the city itself and the novel) in charge. Scorpio's done well, but finds himself confronted with an arrival on Ararat that calls for Clavain's presence. There's a suggestion that the lighthugger Zodiacal Light is in the system and that Inhibitors are catching up with these struggling dregs of humanity. The year is 2675.
In 2615, we find another starship, Gnostic Ascension, pulling into an uncharted system. It's Quaiche's last chance to prove to the horrifying Ultranaut captain Jasmina that he has the skills to earn his keep on the ship. He sends his personal ship down to an uncharted planet, where he finds more than he could have imagined at a price that is beyond imagination as well.
And in 2727, on the small frozen moon of Hela, Rashmika Els, a 16 year old archaeological prodigy, has unearthed evidence that undermines the beliefs of those who rule the vast cathedrals, huge cities in motion that circle the moon to keep the planet Haldora in view, just in case the miracle happens again. That miracle is becoming a little bit more common of late.