|Masako Ibuki's mother, Hatsue, gave birth to Masako after an affair with a married man. She then married Tatsuro Ibuki, who brought Masako up like his real daughter. Now, 29-year old Masako is busy working as an editor of a women's magazine. Her beauty and intelligence attracts many men, but she always rejects them. She is therefore seen as a well-behaved woman. Actually, Masako is secretly going out with 35-year old Shinichi Fukuda, who works in the Marketing Department. She strongly believes in love, and if she had to choose between love and work, Masako is the kind of person who will definitely choose love. Unfortunately, her partner doesn't agree, and he suggests a "contract marriage" effective for three years.|
Shintaro Fukuda is the eldest son of the Fukudas - a wealthy household that possesses much land. His father, Shinichiro, abandoned his family to be with his lover. Living in such a household, Shintaro learned that people's feelings change, and that trapping somebody in a marriage is a sin. He always has a couple of girlfriends to flirt with, Masako being one of them. Shintaro doesn't believe in eternal love, and getting married on the premise that the two will stay together forever is just nonsense to him. That is why he has been searching for a marriage system that suits his beliefs and desires.
Keiko Tokumaru is Masako's 26-year-old colleague who is in love with Shintaro. Although she works in the same office as Masako, Keiko does not know about Masako and Shintaro's relationship. When she finds out about Masako and Shintaro's marriage, Keiko goes mad with jealousy. She had been just one of the many girls Shintaro was flirting with. Their marriage does not stop Keiko from trying to get Shintaro. She is the "femme fatale" who knows exactly how to catch men's attention.
Tsuguo Inagaki is the husband of Masako's best friend, Michiyo. He is now self-employed and runs a restaurant. The Inagakis are Masako's ideal couple. Though not wealthy, Tsuguo is happy to have realized his dream of opening a restaurant with his wife and child. Tsuguo is so happy, he's afraid that there will be a backlash someday. He had no idea that his worries would soon turn into reality.
Yaeko Fukuda is Shintaro's mother. She truly loves her son and wishes for his happiness. She doesn't want Shintaro to go through a painful marriage like herself. Yaeko is frustrated that Shintaro doesn't care about his public image or reputation.
Tatsuro Ibuki is Masako's stepfather. He runs a souvenir shop in Odawara. Although nobody approved of his marriage with Hatsue, who already had a daughter, his deep love towards her brought the couple together. Tatsuro has brought up Masako like his own daughter, and loves her greatly. His only wish is for Masako to become happily married and give birth to his grandchild.