In a sea village, there is a high school freshman, Da-young, who broke up with her boyfriend after summer vacation. Da-young, who has to write the most memorable thing for her vacation homework, writes down the lies of that summer day, recalling her memories with her ex-boyfriend, Byung-hoon.

Cellist Eun-ae decides to sell the cello on the day she returns from studying abroad.

14-year-old Eun-hee moves through life like a hummingbird searching for a taste of sweetness wherever she may find it. Ignored by her parents and abused by her brother, she finds her escape by roaming the neighborhood with her best friend, going on adventures, and exploring young love.

After a few months of social adjustment training, the North Korean refugee Jina moves to a small studio in Seoul and starts her new life. To bring her father to South Korea, she needs money but no matter how hard she works, the discrimination doesn’t let her save enough money.

Humming centers around the relationship between a sound engineer and a supporting actor working on the post-production of an unfinished film, along with the anecdote of a deceased actor.

One winter, a note circulates spreading rumors, stirring up the Korean Military Academy. Jiwoo, who despite his confident attitude hasn’t secured a recommendation letter, and Hoon, a graduate dreaming of assisted suicide in Switzerland, encounter someone else at the Academy during the quiet night.

Today is the day before the presidential election of the prestigious agricultural school. Fine elections for 15-year-olds blinded by power will begin.​