Anna and Isaak are on the run with, hot on their heels, Belinski, the head of security. In Baikonur, Fef is convinced that his sister Irina is hiding something about her husband. At the cosmodrome, Mikhaïl and Réva suspect a hack at the origin of the accident. Anna joins the tracking station where Gilgamesh lives.

Lydia and Réva understand that the American satellite has been hacked from the cosmodrome. Their investigation leads them to the MIR archives. Questioned by Belinksi, Gilgamesh refuses to speak. In the middle of the irradiated zone, Anna and Isaak manage to reach the landing point of the Soyuz.

The International Space Station finally responds: the crew is alive and well. Relieved, Durkov confirms the rescue mission, so Anna prepares for the big departure. Fef and Isaak find the traces of the cosmonaut killer. For her part, Lydia goes through the archives of MIR and ends up finding the anomaly that could explain everything.

Isaak discovers the events that took place aboard the MIR station 25 years earlier and unlocks the secret of the killer's identity. In the damaged station, covered in frost and soon deprived of oxygen, Anna finds part of the crew and tries to bring everyone back to Earth.