The second book of the “Chronoagent” cycle. Who said that there were no aviators in the Middle Ages? And what if, in one of these romantic worlds, a phase transition suddenly appears and the operation of a powerful disintegrator is detected — a device threatening catastrophe for the world? A top-class Chronoagent, Andrey Korshunov — in the past an ace and participant in air battles of the Great Patriotic War — goes there, though not in a “Yak,” but with a sword in hand, to set things right. With confidence in victory… and with no hope for rest. Because after this “assignment,” there will surely be another, and then another — somewhere “hot” in the future or the present, where a breach of the Black Vector of Counteraction has been recorded. It faces a strong and ruthless enemy intent on seizing thousands of parallel phases of the worlds, distorting history and turning the inhabitants into obedient performers of their evil will.