It's summer in Edinburgh, the city hosts an annual festival that attracts hundreds of thousands of guests from all over the world... How Inspector Rebus hates this time! The police phone numbers are ringing out: street thefts, fraud, calls threatening to detonate a bomb. And here’s something extraordinary: in one of the nooks and crannies of the medieval “forbidden city,” walled up under the historical center of Edinburgh, the corpse of a young man was discovered. Apparently, here, in a gloomy dungeon, a ritual of painful execution was performed. What is this - punishment for betrayal as a warning to others? But who are these “others” then? Members of a religious sect of fanatics, fighters of a secret terrorist organization, members of criminal gangs? John Rebus will get to the bottom of the truth, although he will be on the verge of death, and having learned who his savior is, he will once again be surprised by the vicissitudes of fate.