This anime series is set in a not too distant future after sea levels have risen and most of the world is flooded. Our protagonist is Natsuki Ikaruga, a young man who lost one of his legs in an accident. He returns to his home town and finds a humanoid robot, named Atri, amongst his late grandmother's possessions. He considers selling her to pay for a new prosthetic leg but she claims to be self-aware and offers to 'be his leg'. Over the course of the series he learns more about Atri's true nature and his grandmother's work.
I thought this was a solid series. It quickly introduces us to this flooded world and key characters before the story gets going. Once underway the story is interesting with likeable characters and a sense of mystery regarding Atri. The animation and character designs are both pretty good. As the story progresses one grows to care more about the characters; leading to an emotional finale that nicely wraps up the story rather than angling for a second season. Overall I wouldn't say this is a must watch but is still worth watching if you enjoy the genre.
These comments are based on watching the series in Japanese with English subtitles.