The Outside Context Problem: the concept that defines the novel. Something the Culture has no framework for encountering, no protocol for responding to, no prior experience that maps onto it.
Chapter 2: Not Invented Here
The Culture's Minds debate what to do about the Excession in a series of message exchanges that are the novel's structural innovation: epistolary chapters between ship Minds whose names and personalities are the book's most memorable characters.
Chapter 3: Uninvited Guests
The human strand: Byr Genar-Hofoen and his history with Dajeil Gelian, a relationship whose unresolved ending turns out to be connected to the Excession in ways neither of them understands yet.
Chapter 4: Dependency Principle
The Affront, an alien civilisation that practices deliberate cruelty as cultural expression, become involved in the situation around the Excession. Their inclusion raises the novel's central question: how does the Culture respond to something that genuinely offends it?
Chapter 5: Kiss the Blade
Mind-to-Mind communication about the conspiracy forming within the Culture to use the Excession for political ends. The Minds plotting against their own civilisation's principles are the novel's real antagonists.
Chapter 6: Pittance
The Pittance: a Culture habitat at the edge of things, where Dajeil Gelian has been waiting for forty years. Her isolation and its cause become central to the novel's resolution.
Chapter 7: Tier
The Tier: a vast artificial structure of nested habitats, and the setting for Genar-Hofoen's mission to the Affront. The novel's alien contact strand develops here in full.
Chapter 8: Killing Time
The conspiracy among Culture Minds approaches its critical moment. The ships involved have decided the Excession offers too great an opportunity to ignore, and they are willing to act against Culture norms to exploit it.
Chapter 9: Unacceptable Behaviour
The Excession responds. What it does and how it does it answers the question of what kind of entity it is - not the answer anyone expected, and not one that leaves the conspirators in a comfortable position.
Chapter 10: Heavy Messing
The aftermath of the Excession's response. The conspiracy is exposed, the Affront situation resolved, and Genar-Hofoen and Dajeil's relationship reaches its conclusion. The novel ends with the Culture having learned something about itself.
Chapter 11: Regarding Gravious
The fate of the conspiring Minds: accountability within a civilisation that has no prisons, no punishment infrastructure, only the social weight of what other Minds think of you.
Chapter 12: Faring Well
A closing chapter about what the Excession was and where it went, and the question of whether the Culture passed whatever test it may have been administering.
Epilogue
An epilogue: the Sleeper Service, the eccentric Mind at the centre of the novel's final act, departs. Its nature and its choices during the crisis are the book's most sympathetic portrayal of what it means to be a Culture Mind.