Joon Hyeok is an unpopular musician whose life has hit rock bottom. He had already broken off his relationship with his older sister, Joon Hee, when her son appeared before him. His nephew developed Obsessive–compulsive disorder after his mother divorced his stepfather. Joon Hyeok takes his nephew in and looks after him. Joon Hee divorced her physically abusive husband after 12 years of marriage. She moved into an inexpensive apartment and now faces losing custody of her son to her ex-husband and his mother.

Ji Sun Woo is an associate director of a family clinic with a perfect life—a great career, married to a handsome, young-looking man, mother to an adoring son, and surrounded by seemingly caring friends. She couldn't be more content. Lee Tae Oh, her husband, is an aspiring movie director. However, when his temptation leads him to betray Sun Woo along with the people around her, she gets driven to revenge. The perilous twists-and-turns of a married couple's life unfolds.

Set in a teahouse in Myeong-dong, Seoul right after the end of the Korean War, The 12th Suspect follows the suffocating psychological showdown that takes place between a detective and the 11 suspects who find themselves caught up in a murder case.

Park Yoo-Ha studied hard in medical school and finished her intern course. She works hard to become a doctor due to her father. Her father raised 4 children by himself and her oldest sister also sacrificed for the family. Park Yoo-Ha is not interested in other people. Suddenly, her father marries a woman rich enough to own a building. Meanwhile, Jung Eun-Tae works as a doctor. He volunteered for performing medical service abroad, but he comes back to Korea. Jung Eun-Tae is not interested in marriage, because his father placed priority on his medical work over family and Jung Eun-Tae believes he is like his father.

Young Eun lived with a family ever since she was an orphan and then fell in love with Do Hyun who is 5 years older than her. However, Do Hyun's family did not approve of Do Hyun dating Young Eun. As a result, Young Eun eventually left Do Hyun and marries a doctor, Joo Kyung Woo. Although Kyung Woo acts like a gentleman, he is actually a mama's boy with multiple and complicated personalities. Though he treats Young Eun well, he believes everything his mother tells him and will turn on Young Eun at any moment. Jin Ah is a pediatric medical resident and falls for Do Hyun. But she is unsure of his relationship with Young Eun. Do Hyun decides to marry Jin Ah and after the wedding, Young Eun has had enough of Kyung Woo's mother. She decides to leave Kyung Woo. What will happen between Do Hyun and Young Eun? Will they realize they can't leave without the other?

Yu Hye Chan is 29 years old. Hye Chan is married to Kang Bong Man who is her old classmate in high school whom she despised and hated but later fell for. The story opens with her decision to get a divorce. She has a car accident on the way to the courthouse. When she wakes up at the hospital, she has no memory of her life past age 18. Her husband tries to support her since she is basically helpless now. As she recovers her memory, she also starts to recover a relationship with her husband and begins to fall for him all over again.

Two brothers get into a sudden tragic accident and they both fall into a coma at the same time. A year later, the younger brother Dae-jin wakes up believing he is his older brother Ho-jin.