Absolution Gap is a 2003 science fiction novel written by Welsh author Alastair Reynolds. It takes place in the Revelation Space universe and is a direct sequel to Redemption Ark.

The plot of the novel takes place in four separate time periods. The bulk of the novel is contained in the 2675 and 2727 sections.

Queen Jasmina of the lighthugger Gnostic Ascension wakes Quaiche, a member of her crew, from Reefersleep. She is disappointed with him; despite his promises that he would improve the crew's fortunes, he has not done so. In fact, many of the systems he has explored were filled with extremely valuable artifacts which he failed to detect and were picked up by other ships. As such, she gives him one last chance.

Jasmina sends him to explore the star 107 Piscium and its planets. His lover, Morwenna, is sent with him in the scrimshaw suit, a sensory deprivation device which paralyzes and blinds its wearer until they remove it. On one of the moons of a gas giant he names Haldora (which also seems to disappear every so often for a few fractions of a second), he discovers an alien bridge, whose automated defense system attacks him. He crashes and finds he does not have enough oxygen to survive until his shuttle returns from the other side of Haldora. However, Haldora vanishes and his radio signal reaches the shuttle, which races to save him at maximum acceleration, killing Morwenna.

On Ararat, 23 years after the events of Redemption Ark, Scorpio, a hyperpig, seeks out Nevil Clavain, who has left mainstream society, leaving Scorpio in charge. Scorpio seeks his aid in opening a capsule which has come down from space. Also with him is Vasko, a reasonably competent but naïve young man. They open the capsule and discover Ana Khouri. Khouri informs the colony that humanity is now at war with the Inhibitors. They are getting the relevant technology from Aura, Khouri's daughter, who has been modified by the Hades Matrix, an alien data repository. However, Skade has kidnapped her from Khouri's womb. Clavain and Scorpio lead a team who discover Skade in her crashed ship, which has been attacked by the Inhibitors, causing its Cryo-Arithmetic Engines (a cloaking device) to malfunction and cover the ship in ice. Skade agrees to give the colony Aura in return for Clavain's being tortured to death. Clavain agrees, but tells Scorpio to throw his corpse into the sea (where the Pattern Jugglers absorb him and reunite him with Galiana and Felka). The survivors are attacked by Inhibitor machinery, but Remontoire, a Conjoiner leading the war, protects them from space.

Back in the colony, the leaders debate as to what to do next. They eventually decide to leave. Meanwhile, Captain Brannigan of the lighthugger Nostalgia for Infinity has been preparing to do so. After some deliberation, some fourteen thousand of the over 150,000 colonists board the ship, and it leaves. In space they meet Remontoire, who gives them Aura's technology to defend themselves. The leaders debate whether or not to go to the moon Hela (which Aura suggests they do) or Yellowstone, to help evacuate the planet. They decide to do the latter, but find they are too late; by the time they reach Yellowstone (in 2698), it has been overrun. As the crew collect the last refugees attempting to escape the system, a minor mutiny breaks out amongst the upper echelons, in which Scorpio's leadership is overturned and the other leaders take power as a group. This is due to Scorpio electing to rescue the last refugees off a shuttle that had been contaminated by the Inhibitors. After the final disputes are settled, the ship is redirected towards Hela.

Rashmika Els, a 17-year-old girl, leaves her home on Hela to search for her long-lost brother Harbin, who left to join the Cathedrals years before. The Cathedrals were set up by Quaiche after the 2615 timeline and constantly move across Hela (making use of various propulsion systems, such as legs and tracks) to "observe" Haldora and its disappearances (known as "vanishings"). It uses special indoctrinal viruses to maintain religious faith amongst its supporters, although certain areas, such as Rashmika's town, are exempt. She joins one of the caravans, a massive vehicle composed of several smaller units, to get to the "Permanent Way", where the cathedrals can be found. She has the ability to tell whenever people are lying to her, which makes Quaiche very interested in her. He uses false evidence to convince Rashmika that Harbin has become a supporter of the church. In fact he is dead. She arrives at Quaiche's Cathedral and begins working for him.

In the Cathedral she suffers nightmares about a race called the "Shadows", who exist in a parallel Brane to our own. Their universe has been consumed by a rogue terraforming agent, and they are trying to join Rashmika's. They had shown the Scuttlers, the long-extinct inhabitants of Hela, how to build a machine that could bring them across. In return, they would destroy the Inhibitors. However, the Inhibitors allegedly destroyed the Scuttlers first.