The distant future, a dying Earth, the last city of humanity - a giant Blade piercing the entire thickness of the atmosphere. Both the skyscraper and the planet are divided into warring zones. In some, futuristic technologies have been created, in others, inventions beyond the level of the 20th century are impossible. Somewhere there are only machines no more complex than steam engines, and at the very bottom pre-industrial society vegetates. Posthuman angels, inhabitants of the Heavenly Floors, are secretly preparing an operation to capture the entire Blade. Quillon, their agent among the “subhumans,” learns that they have decided to eliminate him; the information he possesses must under no circumstances be given to his enemies. There is only one slim chance of salvation - you have to leave the city and go into the unknown. The most unusual work to date by Alastair Reynolds, a magnificent example of planetary adventure fiction!