This is based on the Andy Weir book by the same name. It is ultimately a buddy movie between the amnesiac but competent Ryan Gosling character and an alien from a distant star system. Their home planets are both menaced from a life form from out of space. The bug eats stars, somehow without being incinerated or re-radiating the energy they consume, thus imperiling their dependednt planets. The two characters are sent to the one star in the neighborhood which is not being similarly doomed, meet, learn to communicate, and team up to solve the scientific mysteries needed to save their civilizations. The filmmakers manage to keep the story moving at a good pace and the actors (one of them generated) sel it all as hard as possible, and I thought it all worked. I am hoping to see more science fiction films that try so hard to stick to plausible science and which find ways to make cooperation as compelling a story motivator as conflict.