A novel from the master of Russian science fiction, continues the cycle "Spacewalkers." Patriotism, scientific concepts and valiant heroes. Darislav Volkov leads another expedition, but now the Salute escort goes to the Dragon Castle, grown by terrestrial pterosaurs in the depths of the dark Universe. Vsevolod Shapiro, a physicist from the "neighboring" metaverse of the Multiverse, studies Tmir and works on the theory of the antiverse, but he faces another, secret task. The portal brings Volkov, Shapiro and their companions to a strange place where weapons and combat vehicles are not produced, but grown from a kind of "spore." Can they go back? Will they be able to cope with the dragons that suddenly came out of suspended animation? The cold mind of Tmir conceived to cleanse our universe from the "dirt and garbage" of other civilizations. But earthlings are able to solve any problem that threatens their homeland.