This drama is adapted from the manga of the same name by Takashi Iwashige, and tells the story of a forbidden four-corner relationship between a man and a woman in their 30s. Sakurai Shun (Shigeoka), a salesperson at a house manufacturing company who lives in Tokyo with his wife, goes to Kagoshima alone, but meets his first love, Takeda Hana (Araki), a classmate, and awakens to forbidden love. Soon, they develop a love-hate four-corner relationship with Shun's wife, a salesperson at a competing company and a former rival.