Chiwa Takanashi is a single 23-year-old retail worker during the day and a bar hostess at night, working to pay off her father's debt. One day, a rich businessman, Hokuto, tells her, "marry me and I'll pay off the debt", but Chiwa rejects his proposal. Later, Hokuto's true reason for marrying Chiwa is revealed.

Hokuto persuades Chiwa to get married and they are now officially husband and wife. Hokuto takes Chiwa to his parents to announce their marriage. His relatives give a cold response to the announcement because his mother is his father's mistress. A new part-timer at Chiwa's workplace, Yu Yagami, says he is attracted to her. Will this trigger a new love affair?

Chiwa witnesses Hokuto talking happily with Misaki, the intelligent and beautiful president of Michel Hearts. She also meets Hokuto's beautiful secretary, Taeko Soma, who tells Chiwa, "I know Hokuto better than you do". Chiwa decides to visit Hokuto's father, Seiji, at the hospital, but when Hokuto later finds out about this, he gets angry and tells her something unexpected.

Hokuto and Chiwa are finally married. Hokuto is denounced by the Mamiya family because he humiliated their company by disclosing the accounting fraud. The relationship between Chiwa and Yu becomes awkward since she kept the marriage a secret. Chiwa becomes jealous of Misaki and Hokuto's relationship. Soon after, Hokuto and Chiwa's marriage is revealed in a tabloid.

Chiwa thanks Misaki for arranging the party, but Misaki says she did it for Hokuto, not her. Chiwa is now the corporate marketer at Yamaguchi. Chiwa accidentally sees an article about Hokuto and Misaki's relationship and is shocked to find they had been dating. She confronts Hokuto, but all he says is, "that was in the past. I only consider her a business partner now, nothing more".

Chiwa is worried that Hokuto might not love her. Chiwa visits Seiji at the hospital and feels worried once more when she sees the gorgeous flowers by his bed brought by Misaki. Due to her distrust towards Hokuto, she gets angry and they get into an argument. Soon after, Mamiya Fiber's business partner, Rene Claire files for bankruptcy and Hokuto is faced with a grave predicament.

Misaki tells Chiwa that only she, herself can support Hokuto. Hokuto is convinced that Misaki's ideas can get them back some of the losses from Rene Claire's bankruptcy, but he also realizes something is wrong with Chiwa. Yu starts his own business and offers Chiwa a position. Hokuto witnesses Chiwa with Yu and gets angry. Their relationship worsens, and Chiwa's birthday approaches.

Hokuto is stabbed by someone. While he is hospitalized, Takayuki closes a deal and saves Mamiya Fiber from its crisis. Chiwa finds out that Seiji has pancreatic cancer but Hokuto refuses to visit him. Hokuto tells Misaki he can't work with her anymore because he doesn't want to hurt Chiwa's feelings. Chiwa goes to Hokuto's house to find out who killed his mother...

Seiji's illness has worsened and Hokuto finally decides to see his father. The two finally reconcile before Seiji dies, and in his will, he states that Hokuto would be the president of the Mamiya Group. The Mamiya family are dissatisfied with this and Reiko demands Hokuto get a DNA test to prove he is Seiji's son.

Hokuto and Chiwa find out that Satoru killed Yoko. They try to keep Chiwa's pregnancy a secret but Saori finds out. Misaki offers a bodyguard for Chiwa so she can be alone with Hokuto for a night. Misaki threatens Hokuto that she'll put Chiwa's life in danger in order to be with him. When Chiwa is heading home from work with Yu, she realizes that something is wrong with her bodyguard.

Chiwa stays at Yu's apartment to hide from her bodyguard. Hokuto comes to Yu's apartment and tells him to give up on Chiwa. Yu accepts, but only if Hokuto lets Yu punch him. Hokuto leaves the Mamiya Group for Chiwa's safety, and the two move to the countryside. They spend a peaceful time there, but Chiwa starts to feel that Hokuto should go back to working as a businessman.