Phases of the Moon.

Osanai Kei enjoys a peaceful and happy life with his wife Osanai Kozue and daughter Osanai Ruri, but his wife and daughter die in an accident. Osanai Kei's life suddenly changes. One day, a man named Misumi Akihiko visits Osanai Kei. Misumi Akihiko tells him that on the day Osanai Kozue and Osanai Ruri died, Osanai Ruri, who was a complete stranger to him, was coming to see him. Misumi Akihiko tells him about a woman named Masaki Ruri, who he once loved. These people, who don't seem related, connect under the name of love.