This French Sci-fi drama follows the first manned mission to Mars; as they arrive in orbit they learn that they were overtaken by a mission sent by an American concern. However contact with that crew is lost so our protagonists are ordered to investigate. They find what appears to be a survivor; he wasn't one of the American crew though... he appears to be Vladimir Komarov, a Cosmonaut who died re-entering Earth's atmosphere in 1967! Over the course of the series the crew, in particular Jeanne Renoir the ship's psychologist, try to find out who or what Komarov really is. They are also concerned about how they will ultimately leave the red planet.
If you want lots of action in your sci-fi this might not be for you but if you want intelligent and intriguing science fiction then this should keep you gripped. There may not be action but there is plenty of tension when various things go wrong. Things turn interesting when Komarov is found; there is a real sense of mystery about whether it is really Komarov or something else altogether. I liked how they incorporated the very real story of the first death in space into the plot. There are some weaknesses of course; particularly when a rather aggressive second US team arrives. The cast do a solid job; with Hélène Viviès standing out as Jeanne. The ending does leave things open for a second season; I'd certainly watch if one is made. Overall I'd certainly recommend this series to fans of the genre.
These comments are based on watching the series in French with English subtitles.