Magician/spy Bob Howard has to save his love interest Mo from the machinations of a terrorist organization with occult ambitions. Bob Howard, a former hacker now conscripted into Her Majesty's Occult Services, works for the British secret magic spy agency the Laundry, stopping dangerous men and women from using magic to end the world.
At the beginning of the book, Bob is a systems administrator for the Laundry, although his ambitions (and desire for a better pay grade) have lead him into testing out for field agent status. His cool head under fire, not to mention his aptitude with computer-assisted magical working, earn him a dual appointment: while he continues to maintain the Laundry's system integrity during the day (and continues to report to bosses-from-Hell Harriet and Bridget), Bob is also sent on globe-trotting secret assignments by picture-perfect English spymaster Angleton.
During one of these missions, Bob meets Mo, a logic professor with interests in physics and computation that have lead her dangerously close to discovering the secret world where magic meets math. After helping save her from the sinister American magical spy agency the Black Chamber, Bob is assigned to help protect Mo from the Mukhabarat, a Middle-Eastern terrorist cell seeking to exploit Mo's magical potential. During the assignment, Bob, recently estranged from his sometimes-ladyfriend Mhari, grows attracted to the redheaded professor.
Bob and Mo are sent to Amsterdam, ostensibly to identify the mystical symbols Mo was exposed to during a Mukhabarat attack, although Angleton is secretly using Mo as bait to draw out the Laundry's foes. The two hapless spys dig through the Atrocity Archives, a record of Germany's WWII efforts to summon game-changing supernatural entities. However, the Mukhabarat cell proves more powerful and resourceful than expected, and they capture Mo by pulling her into another universe, code-named OGRE REALITY.
The Laundry mounts a rescue operation into the alternate reality, spearheaded by Bob and a team of SAS troopers. Through the portal, the heroes discover a dying world, the product of a changed history in which the Nazis succeed in summoning a "frost giant" that has sucked almost all the heat energy from the universe. The mission seems to go off without a hitch: the team recovers Mo in an abandoned SS fortress and plant a nuke to sterilize the world. However, as the heroes head back towards their own world, Bob figures out the sinister truth: the whole operation was a ruse by the evil entity summoned by the Third Reich, which plans to use the energy of the nuclear explosion to catapult itself into the universe of the Laundry.
Bob confronts the entity, who has possessed one of the SAS commandos, and manages to trick into into dis-incarnating. He then rushes to stop the detonation of the device and escapes to his home universe. The novel ends with Mo moving into Bob's company-owned flat, and the promise of future romance.
Best part of story, including ending:
I enjoyed the originality of the concept and the blending of genres (spy, fantasy, humor, and a touch of horror).
Best scene in story:
The book's climax, in which Bob and a team of SAS commandos must infiltrate a universe in the throes of entropic death to save Mo, showcases the best of Stross' writing, marrying careful intellectual description and the unfolding of a mystery with modern fantasy action sequences.
Opinion about the main character:
Bob is likable to a certain kind of reader because of his sarcastic demeanor. He's a part of a massive system with world-saving responsibilities, but his anti-authoritarian streak manifests in his cynical reactions to the simultaneously terrible and mundane things he sees every day.