What Is Love?

I'm so happy. But he's not my lover.

Teruko is a 28-year-old office worker. 5 months ago, she fell in love with Mamoru at first sight. Since that time, she has not cared about her work or her friends. She then loses her job and her friends look at her coldly. Yet, Teruko is happy as long as she is with Mamoru. Meanwhile, Mamoru thinks Teruko is an easy woman for him to not love. Teruko's unrequited love grows deeper.