Hyo Sim has carved out a successful career as a personal trainer at TS Fitness, but her family obligations start to weigh down on her. Being the only girl among her four siblings, she is always the one handling the less desirable tasks and financial woes for her eldest brother, who focuses solely on his own family, her intelligent yet egocentric second eldest brother, and her youngest brother, who chases dreams of financial windfalls. Her only refuge in this constant battle against her demanding siblings is her mother, who unfortunately only sides with her brothers. Faced with adversity on all fronts, Kang Tae Ho, a meticulous new gym member, becomes the catalyst that pushes her over the edge. She decides that nothing else matters except regaining control of her life, and she takes the first step toward finding peace in her life.

Even though she is unable to have a proper wedding due to the disapproval of in-laws, Yeon Hee has been a great mother, wife, and daughter-in-law for 25 years. However, everything changes when Yu Na, her husband Jun Ho's mistress, appears and Yeon Hee's health deteriorates as well. Unlike Yeon Hee, Yu Na is a woman who abandons her sacrificial husband, Jae Kyung, and her son, Ha Neul, and chooses Jun Ho for success although Jun Ho is married and she had already rejected him 10 years ago. The four completely different people try to form a different kind of family and try hard to remain together.

Eun Jae is a pretty girl with a good personality who excelled in art. However, when she starts dating Kyo Bin, her brother's friend, she becomes pregnant and ends up marrying him. Due to a brutal married life and constant conflict with her in-laws, she suffers a miscarriage. Her husband, Kyo Bin, constantly flirts and cheats with other women, but Eun Jae is the one forced to sign divorce documents because of an incident. It turns out the woman whom Kyo Bin was seeing on the side was Shin Ae Ri, Eun Jae's friend of over ten years and someone whom she considered a sister. After being abandoned by the people she trusted the most, she plans an elaborate plan to take them down.