At high school Ryouko introduces her boyfriend, Otoumi, to her best friend, Yukari, creates a deep friendship between them. Long after Ryouko's relationship with Otoumi ended, Yukari and Otoumi continue to be friends.

After five years Otoumi slowly becomes aware of his changing feelings for Yukari that leave him confused. Yukari, on the other hand, finds that Otoumi is acting weird and becomes suspicious.

When Outomi reveals that he kissed one of his co-workers that confessed to him before, he also starts to wonder about his own feelings towards Otoumi.

Prequel; Story continues in 'Dear Green'.