Cosmonaut Oleg Bogdanov gets severely injured during EVA at ISS. There is no way he can be brought back to his current state, and he is slowly dying. The female thoracic surgeon, Eugenia Belyaeva, is selected from several specialists to fly to space and try to save Bogdanov. She is a very professional surgeon, but not a very happy person in normal life: a single mom with a teenager daughter who still cannot forget the death of her husband and believes that she was the reason for it. The success of a surgery at the ISS is not guaranteed, to say the least, and this medium-complexity surgery, if done on Earth, can easily turn into a complete disaster in space.