Higashiyama Yui works as a director at Net Heroes, a web production company. Due to her workaholic father and bad experiences in the past, she loathes working overtime. Even 2 years ago, she broke off her engagement to Taneda Kotaro because he was a workaholic. At her job, Higashiyama Yui always leaves at the end of the regular working day and never works overtime. She tries to be as efficient as possible and productive during her normal working hours. After she leaves her office, Higashiyama Yui normally drinks beer at her regular Chinese restaurant. Her peaceful days begin to change after a new department head arrives at work.
Shirai Yui has decided to take a new job as a secretary at the law firm of her childhood friends, the Kami brothers. Yui has feelings for her older brother, Soichi, but when they meet again for the first time in 18 years, she is confused to find that Soichi has become a cool, unsmiling man. Meanwhile, her younger brother, Yushiro, has always loved Yui, but has not been able to express his feelings. And Soichi has been unable to express his love for Yui due to a childhood trauma. The love stories of Yui, who loves Soichi, Yushiro, who loves Yui, and Soichi, who is jealous of Yui's close friend, all intertwine.
Gong Ah Jung, a level 5 Ministry of Culture official, gets entangled in a web of lies when she mistakenly lies that she's married to Hyun Ki Joon, a noble hotel manager from an affluent family. Their relationship is further complicated when Ki Joon's ex-fiance and a close friend of his brother's, Oh Yoon Joo, reappears in his life
Wi Mae Ri is the cheerful, pragmatic daughter of a failed businessman who had grown used to being constantly on the move to escape from debtors. She becomes fast friends with the free-spirited indie singer, Kang Moo Kyul, when she nearly ran him over in a car. Meanwhile, her father, Wi Dae Han, is saved from his debtors by his old friend, Jung Suk, who had just returned from considerable success in the Japanese entertainment industry. Jung Suk, who had harboured a secret love for Mae Ri's mother, sets up a deal with Dae Han to have Mae Ri marry his son, Jung In. In a desperate attempt to escape this predicament, Mae Ri begs Moo Kyul to pose as her husband, and finds herself in even more trouble than before when her father proposes a 100-day period in which she has to divide her time equally between Moo Kyul and Jung In, after which she has to decide who to marry.
After being dumped by her boyfriend just before their 100 day anniversary, Ha Young meets a college guy named Hyung Joon whom she accidentally hits in the face with a can causing him to scratch his Lexus. He demands she pay him $3000 on the spot, but she escapes, leaving her wallet behind. Hyung Joon, not satisfied with this, stalks her, demanding money to pay for his car. Since Ha Young is a poor high school student, Hyung Joon writes up an "Enslavement Agreement" to ensure she pays for the damage to his car. Through this agreement, Ha Young finds herself thrown into a nightmarish slave life for 100 days; cleaning his house, running his errands, doing his homework, even cleaning his car.
By accident, she discovers that the damage to Hyung Joon's car only cost $10, so she decides to take her revenge. However, before she knows it, Hyung Joon has shown up at her house as her new tutor! He once again takes advantage of her, but soon Ha Young finds herself falling head over heels for him. But what happens when he drops out of her life just when she needs him most?
By accident, she discovers that the damage to Hyung Joon's car only cost $10, so she decides to take her revenge. However, before she knows it, Hyung Joon has shown up at her house as her new tutor! He once again takes advantage of her, but soon Ha Young finds herself falling head over heels for him. But what happens when he drops out of her life just when she needs him most?
Byun Ji Sook has always had a hard life with her father constantly going into debt and being chased by loan sharks. She desperately wants to know what life is like if she was born into a better family and didn’t have to worry about money all the time. When a series of circumstances brings Ji Sook to Eun Ha, a woman from a wealthy family who strongly resembles Ji Sook, she grabs hold of the chance for a better life and assumes Eun Ha’s identity and begins to live her elite life. She meets Min Woo, a chaebol heir who is mistrusting of the people around him. But when he realizes that Ji Sook is not like the other women he has met, he is drawn to her. How long can Ji Sook keep up the charade and hide her true identity?
