Oh Dong-Joo has dated only one man in her life and they have dated for the past 10 years. Suddenly, the man breaks up with her, leaving Oh Dong-Joo shocked and confused.

Yoon-seul experienced something unforgettable at the age of 19. Occasionally, when she returns to her hometown, she confronts Jin-chul about his failure to apologize for a decision he made at the same time.

Im Hun-Sik has lived his life for his family. One day, he hears news that singer Jin Choo-Ha is returning to South Korea. Im Hun-Sik has liked Jin Choo-Ha since he was young. He is excited by the news but soon finds himself being pulled back by his responsibilities.

Yeon-Soo is a veteran police officer. She appears cold to others, but she actually has a warm heart. She begins work on an island, where she finds unacceptable things taking place. Yeon-Soo begins to investigate the ordinary residents there who do not seem to feel any remorse over the events.

Byung-Doo is part of a voice phishing group. His job in the group is to withdraw money from the victim's account and deposit the money into bank accounts they control. One night, Byung-Doo and his partners cause big trouble. They are then chased by Boss Kong from their criminal group.

Joo-Young works at a small office and is indifferent to the world. Wanting to separate her personal life from her wor, she buys a used cellphone with the help of which she finds out middle-school student Hee-Joo, the previous owner of the cellphone, is being bullied on social media. Joo-Young, who normally doesn't care about other people, tries to save Hee-Joo.

Sometime in the near future, a father is diagnosed with an incurable disease and told he doesn't have much time left to live. The man begins to build an AI clone of himself for his son, not wanting him left all alone after his passing.

Byung-Tae is a pension owner with nothing to live for, while Kyung-Soo is a pension customer who wants to die. Their lives change when mysterious woman Yoo-Rim appears in front of them carrying a lot of money.

Hong Hee-Soo used to be a popular movie director, but nowadays she is in a slump. While looking for a writer for her new movie, she is re-united with ex-boyfriend Kim Pil-Ki who after he breaking up with her, became a successful dramatization writer.

4 years ago, Young-Hoon and Seung-Bong were friends and high school students. Due to a fateful decision they made, their friendship was changed.