After five years of wandering around the Pyatizon, former military helicopter pilot, and now criminal and deserter Gennady Khomyakov, nicknamed Diamond Mongoose, was finally arrested. Because of his phenomenal abilities, he ends up in the secret research center “Svetoch”, where he begins to be subjected to exhausting, inhumane experiments. And when a technical failure occurs during the next experiment, Khomyakov without hesitation takes advantage of the moment and runs away from his tormentors. Hiding from pursuit, he goes to Novosibirsk, where he has a chance to find the answer to his phenomenon. However, standing in his way is both the “Lightlight” and a powerful third force - the mysterious and cruel Smart Guy. Will Khomyakov manage to get something that can return him to normal human appearance and freedom, and open a way out of the Zone for him? It’s hard to say, because the current winter in Novosibirsk is more ferocious than ever, and the Diamond Mongoose is destined for such tests that the conquerors of the North Pole and Antarctica never even dreamed of in their nightmares...