A love triangle develops between a shy office worker, a part-time worker and a CEO.

Aoishi Hanae is a plain, inconspicuous office lady who has had no experience in love and no boyfriend. On her 30th birthday, she happens to end up drinking with Tanokura Yuto, a cool university student nine years her junior who is also a part-timer at her company, on the way home from a welcome party for new employees. Hanae gets drunk. When she wakes up the next morning, she finds a naked Yuto sleeping next to her. She has her first experience and first boyfriend out of the blue. Even when Hanae and Yuto go on to date, it is a daily process of trial and error because everything is a first for Hanae, including an amusement park date, a sleepover, Christmas Eve or a couple's trip. To complicate matters, she also gets a proposal from Asao Yu, the CEO of an Italian food company who is popular with women, and a love triangle develops.