Rena has been single her entire life. By day, she works in the general affairs department of a large corporation called Hasebe, but she hides a secret: at night, she works as a hostess at a bar to cover her younger brother's law school tuition and other urgent expenses. One day during a lunch break with her close friend and colleague Kyoko, Kyoko's older brother Shun, the handsome and polished managing director of the company, joins them. Shun is widely admired by female employees for his gentlemanly demeanor, and even Rena finds herself charmed by his kind and graceful manner. That same evening, however, Shun walks into the bar where Rena works as a customer. To her shock, his personality is completely transformed: he flirts aggressively and exudes a seductive, manipulative air that is the opposite of his daytime persona. Rena frantically tries to conceal her identity, but she cannot maintain the charade. Resigned to being exposed and fired, she drinks heavily in despair. When she wakes up the next morning, she finds herself lying next to a naked Shun in his bed.

Shun, the managing director of Hasebe and the son of the company president, is 28 years old, strikingly handsome, and exceptionally capable at work. To most of the staff, he appears to be the ideal gentleman, but this public image is a facade. In truth, he is a scheming, dark-hearted man with a past that has left him cynical toward women, especially those who work in nightlife. Once he learns Rena's secret, he seizes the opportunity to control her. He uses her hidden job as leverage to force her into becoming his personal assistant, all while toying with her emotions. Despite his manipulative behavior, Shun finds himself increasingly drawn to Rena's stubborn, resilient nature and her genuine dedication to supporting her family. As the story progresses, his feelings shift from mere amusement to genuine affection, though his possessive and underhanded methods continue to create tension.

Rena, at 26, is a hardworking and determined woman who has never had a boyfriend. She carries the heavy burden of supporting her younger brother, who aspires to become a lawyer. Her strong-willed personality and pride often clash with Shun's arrogant and scheming tactics, yet she cannot completely suppress the attraction she feels toward him. The central conflict of the narrative revolves around their power imbalance: Shun holds the threat of exposing Rena's double life over her, while Rena struggles to maintain her dignity and resist his advances.

The story also introduces several supporting characters who add complexity to the romance. Kyoko, Rena's confidante and Shun's half-sister, has a strained relationship with her brother due to his overbearing perfection. The company doctor, a mutual friend from Shun and Kyoko's high school days, occasionally appears as a neutral observer. Shun's ex-girlfriend Ayumi, an accomplished department head at another company, resurfaces to create romantic interference. Additionally, a jealous receptionist named Suzuki targets Rena with workplace harassment after she becomes Shun's personal secretary, and an aggressive client from a partner company repeatedly pressures Rena, forcing Shun to step in and protect her.

After numerous misunderstandings, moments of jealousy, and the gradual unraveling of Shun's guarded heart, the pair eventually confess their feelings for one another. Shun, whose obsession with Rena has grown into a deep and possessive love, proposes to her, but Rena remains hesitant and guarded. They eventually marry, though not without further emotional turmoil. A year into their marriage, Shun secretly prepares a surprise wedding ceremony for Rena, who had insisted she did not need a formal celebration. The story concludes with the couple exchanging vows in a snowy winter setting, surrounded by close friends and family. An additional side story follows Kyoko's own romantic development with the company doctor, tying up the fates of the secondary characters. The series ends on a happy, harmonious note, with all major characters finding their own form of happiness.