1999— The Age of Apocalypse, where violence was rampant. In those days, nothing was easy. A story about the love and friendship of girls, which was hotter than any other summer... Joo-young and Ye-ji’s relationship is tender but ultimately feels like an impossible one.

Bored and lethargic Hyunsil becomes impatient after seeing the posting of a poetry contest. For some reason, she wants to be a poet and has composed four poems so far. However, to enter the contest, she needs five poems. Moreover, there is just one day left before the deadline.

Chinese secret agent Da-hee receives intel that a large number of illegal firearms are being smuggled into Korea and is sent to investigate the case. She meets Su-han, who is supposed to help her with the case, but due to his lackluster skills they fight over trivial things. But as their witnesses are suddenly murdered, the two of them quickly become the prime suspects.

In mid '90s, 3 female high school-grad office workers take up English classes together to get promotions and they team up to uncover corruption within their company.

When a school girl disappears, suicide is suspected, and one of her classmates is suspected of having goaded her into it.

Ah-jin, a writer and aspiring professor, joins graduate students Hyun-ah and Woo-soo on an exhibition about the cursed prison "Dwi-ju." Ignoring the dark rumors, they dive into the project. But as their hidden desires awaken, so does the curse-slowly turning their reality into a nightmare.

The main character 'Du-na' is a daily worker who does sales work at the mart. One day, Du-na, who was sick, sends her cat to Mart instead. The company manager, who liked cats that sell goods better than Du-na, dismisses Du-na and hires cat. When she becomes a deadbeat, she visits the cat's mart to get revenge on the cat.

Min-hee, who faces many changes after losing her husband. After her husband's sudden death, Min-hee visits Jeju Island, where her husband had always yearned and experiences a whirlwind of emotions. Mok-ha, a single mom living in Jeju Island, becomes a neighbor to Min-hee who comes down from Seoul and causes various emotional changes.

A high school freshman, Mi-ran, trips on the rope while practicing group jump roping for the school field day. Mi-ran’s novice homeroom teacher, Chae-young, replaces Mir-ran with another student, and Mi-ran feels confused. The next day, Mi-ran trips on the rope again. After arguing with Chae-young, Mi-ran makes a decision that can never be reversed.