Jernau Morat Gurgeh, a professional gamer in the utopian, galaxy-spanning society called the Culture, is recruited by the Culture's special ops branch to infiltrate a gaming event hosted by the nearby galactic empire of Azad -- a game which determines who becomes Azad's next emperor. Jernau Morat Gurgeh is one of the Culture's most famous, and brilliant, professional games' players. The only problem: he's bored. The Culture is a post-scarcity, utopian society that spans the length of the Milky Way, and all the games Gurgeh plays are too sterile, too theoretical. His life has no danger, no consequences, and therefore little to keep him interested.
It's into this setting that Gurgeh finds himself recruited by Special Circumstances (the special ops branch of Contact, which is itself the "first contact" knife-point in the Culture's initial dealings with less advanced societies). They won't tell Gurgeh what the job is until he agrees, only making it clear that he would be gone from the Culture for a long while. At first Gurgeh balks, but his deep malaise -- and some extra blackmailing from a rogue drone who helped Gurgeh cheat in a highly publicized match -- lead him to finally accept.
Contact then tells him about the Empire of Azad, a brutal and barbaric society located in the Small Magellanic Cloud, and about the mind-bogglingly complex and nuanced game that drives all social and political hierarchies in the Empire. During the two year journey to Azad, Gurgeh does his best to learn the game with the help of Flere-Imsaho, a Special Circumstances drone, and the ship's unfathomably brilliant A.I. Mind. He suspects that he himself is being manipulated in a much larger game, but for the moment he neither knows nor cares just what that is. The complexity of the game, also called Azad, seduces and enthralls him. The idea is that the game is sufficiently subtle and sophisticated to provide an accurate reflection of the mental, emotional, and political capacities of those playing it, and thereby fairly determine their place in the Azad society. The worst players occupy the lowest rungs of society; the best becomes the emperor.
When he arrives on Azad's capital planet, Gurgeh is shocked and appalled at the primitive barbarity of this new society. He tries to chalk it up to the uniquely laissez-faire nature of the Culture, but the vicious underbelly of Azad begins to wear at him. But soon the games begin and Gurgeh has interest in nothing else.
The opening rounds are against low-level players: bureaucrats, low-level military officers, and other middling officials. After Gurgeh destroys this initial competition, he is not only matched against more sophisticated opponents (who are, correspondingly, much higher ranked members of the Azad society) but also finds himself facing multiple opponents who band together to take him down. As an outsider, Gurgeh represents a threat to the integrity of the game, and his continuing to win begins to expose the lie that the game reflects a genuine ability to succeed in Azad society.
Gurgeh keeps winning, though, and finds himself -- while between rounds -- sucked into the real-life political machinations of the Empire. At last, Gurgeh squares off against the emperor himself. The emperor reveals to Gurgeh that he knows about the Culture, and that he knows it is far wealthier and more technologically advanced than Azad, but that he will never loosen his grip on his empire. Their match is epic, but Gurgeh maneuvers himself into a winning position. Rather than be defeated, the emperor attempts to kill Gurgeh, but is killed from the deflection of his own weapon when the drone, Flere-Imsaho, jumps between them.
With the emperor dead and the game discredited, imperial control disintegrates and Azad society unravels. Gurgeh realizes this was his purpose all along.
Best part of story, including ending:
The game of Azad, while never fully articulated as to what exactly constitutes its rules and parameters, is an ingenious invention. Banks does a phenomenal job of not only making you believe that such a game exists, but also that, given its complexity, an interstellar empire could organize its internal politics around it.
Best scene in story:
After the initial rounds of the game against relatively easy opponents, Gurgeh's battle with the top military leaders, especially against the highest-ranking Fleet Admiral, really shows the true complexity of the game for the first time. In this round, Gurgeh has to double down his efforts and focus, and the reader is drawn in with him.
Opinion about the main character:
In Gurgeh, I love the sense that, even with the unlimited, free resources available to all citizens of the Culture, a suitably complex person will be deeply unsatisfied and drift into hopelessness.