Hiroshi Matsubara

Kasumi is shocked to discover that her older sister's fiance is the man she first fell in love with five years ago in high school. At the time, he was her high school teacher and ultimately quit his job racked with guilt over their relationship. Kasumi was deeply hurt and struggled for a long time to overcome her sadness. Now the two of them must come to terms with their secret past before the ones they care about in the present are hurt. (mydramalist.com)

At some point, Irie Manato began to withdraw himself from the world. Even when picked on, it's not the real Irie, but an act. However one day he meets a strange girl - Misawa Yui. Yui, who finds the tedium of everyday life unbearable, teases Manato with her almost too upfront and honest manner. Alone and afraid Manato wavers but finds himself drawn to her. But his feelings for Yui are doomed to be unrequited. (mydramalist)

A love story between a young man who has been forced to grow up too quickly, and a young woman with an ailment that has placed restrictions on her life. (imdb)