Hatsukoi no Atosaki

Nishina is doing well at his prestigious company but after divorcing from a loveless marriage, his success at work seems empty. A chance meeting at a cafe brings him into contact with the owner, Miyama, an old high-school classmate. It seems that Miyama has forgotten him until he asks Nishina why he's no longer wearing a wedding ring and what Nishina said to him 10 years ago in high school.
Note: Miyama also appears as a minor character in "After a Storm", set two years before the start of this series.
Included one-shot: Double Line