Stranger in the Twilight

The manga's story begins when the relative of the president of a major company moves with their family to a quiet rural town. There, the family's son Tatsuomi plans his suicide, but is spotted by Riko, a local girl. While Tatsuomi is troubled by many things, Riko still intends to befriend him, and they slowly grow closer. When Tatsuomi's birthday approaches, Riko gives him both a gift and a certain promise.