The novel takes place in a fictional country - Romandy. Alexander is a twelve-year-old schoolboy, the son of an officer of the elite troops of the Central Central Committee, whose civilian goal is to pacify those who do not agree with the tenets of the Party and to destroy those whom Comrade Silin considers an enemy of society. With his best friend Stepan, they are building a tree house - a secret headquarters in which they can retire and talk about their secrets. Everything went according to plan until one day they met a creature with huge wings...