Eun Kang is Ba Da's lifelong friend of 20 years. She helps Ba Da by doing odd jobs for her. When Eun Kang's boyfriend, Tae Ki, passes the civil servant exam, they celebrate with Ba Da and her husband, Cha Won.
Eun Kang goes swimming in the pool after becoming frustrated from an argument with Tae Ki, and Cha Won watches her from a distance. Meanwhile, Ba Da and Cha Won go through a rough patch due to Cha Won's parents.
Eun Kang and Cha Won spend time together. A falling apart between Cha Won and Ba Da begins due to Cha Won's mother. Eun San and Nam Chul have dinner together after working overtime, and later, Eun San witnesses Tae Ki cheating on Eun Kang.
Eun Kang and Tae Ki's relationship becomes worse after he meets her parents. She desperately tries to hold on to Tae Ki, but it's of no use. Cha Won's patience gets pushed to its limits as the clash between Ba Da and his mother deepens.
Eun Kang's family goes after Tae Ki for revenge. Nam Chul lets out all the sorrow and pain he has been holding at Mul Sang, and Eun San worries more about Nam Chul as she learns about his life with his in-laws.
Nam Chul's sudden demand causes a stir among the family members. Ba Da finds out that Gong Ju and Eun Kang met separately. Eun Kang decides to show up at Tae Ki's wedding. Meanwhile, Eun San feels strongly attracted to Nam Chul.
Eun Kang and Cha Won spend time together at the beach. When Cha Won returns home, he gets into a big fight with Ba Da about his mother-in-law. Nam Chul and Eun San become more affectionate and develop feelings for each other.
Cha Won becomes confused when he learns about Ba Da's secret. Ba Da goes on a short getaway with her mom and runs into an old friend. Mul Sang makes a surprise visit to the company while Nam Chul and Eun San are together.
While Ba Da spends time with her mother on a short vacation, Eun Kang and Cha Won have a wonderful time at the amusement park. Cha Won learns Ba Da met Ki Han during her trip. Nam Chul goes to see Eun San and Mul Sang follows him secretly.
Cha Won asks Eun Kang about Ba Da and Ki Han's relationship after seeing them together. Mul Sang, who has now confirmed Nam Chul's affair, sits with him for a talk. As Nam Chul falls deeper into his unfaithfulness, Eun San's greed grows.
Eun Kang and Cha Won cross the line. The next day, Cha Won avoids sleeping with Ba Da. Mul Sang keeps pushing Nam Chul to end things with Eun San quickly, and ultimately, Nam Chul gets forced to call her in the middle of the night.
After learning about Nam Chul's affair from Eun San directly, Geum Ah charges into their studio apartment and unleashes her rage. Eun San tells Nam Chul to divorce his wife. Ba Da gets drunk at the party and returns home on Ki Han's back.
Everyone learns about Nam Chul's affair. Eun Kang tells Nam Chul to end it with Eun San. Kwon Tae Ki shows Ba Da a shocking video of Eun Kang. Cha Won and Eun Kang can't forget about each other and kiss. However, someone is watching.
Ba Da's business gets hit with an unexpected wave and sways out of control. Ba Da lashes out at Cha Won. Jeon Hee wakes up and tells Ba Da everything she saw. Eun San runs into Nam Chul's children while still unable to accept the breakup.
Ba Da confronts Eun Kang and Cha Won at a cafe. Ba Da hands Cha Won divorce papers, and Mul Sang flips his household upside down in anger. Nam Chul and Eun San bump into each other and say goodbye one last time.
Eun Kang becomes annoyed and agitated as she watches Cha Won look desperately for Ba Da. Mul Sang takes matters into his own hands to keep Eun Kang away from Cha Won. Eun San's family goes crazy after learning Eun San is Nam Chul's lover.
Cha Won hesitates as Eun Kang holds on to him, saying they shouldn't end things. Jeon Hee shows up at Mul Sang's house. Dae Bong has a hard time and blames himself for everything. Ji Ok exposes Geum Ah's affair with Dae Geun to Nam Chul.
Eun Kang receives good news. Jeon Hee visits Cha Won and tries to persuade him to get back together with Ba Da. Nam Chul tells Geum Ah not to take it too far but explodes in anger. Ba Da hears the shocking truth about her stolen designs.
Eun San plans to leave for volunteer work overseas, while Nam Chul and Geum Ah opt for divorce. Mul Sang finds out Geum Ah has been meeting with Dae Geun again. Ba Da sues Eun Kang and plans to seduce Cha Won again for her revenge.
Nam Chul and Eun San reunite. Mul Sang household is on the verge of losing their fortune in a scam. Ba Da takes Cha Won's family to Eun Kang's house. As Eun Kang prepares for her first day as a school teacher, she makes her final decision.
