A strict senior and a defiant freshman clash under the SOTUS system—but resistance slowly turns into something tender.

After confessing her love in elementary school to her crush, Maewnam is literally crushed when he rejects her in front of all his friends. He calls her ugly and it's at that moment that she decides to wear a box on her head. Maewnam is really damaged by those events and she hides behind the box, truly believing that she's ugly. Forced to return to school, Maewnam meets Minton and Zero. Minton is sweet, friendly, and new to the school while Zero is a notorious troublemaker who uses his fists to solve his problems. The question is: who's the boy that called her ugly all of those years ago? Is it Minton? Is it Zero? Is it another person?

This series tells the stories of lonely people in the age of social media. The residents of rooms 401 through 410 live alone. Although their lifestyles may be different, they share and confront the same problem, loneliness. For them, social media seems to be the only choice to connect and relieve their loneliness. However, in reality, their loneliness cannot be deleted.

A flood could hit Bangkok, so, to avoid problems, BB and Bambam are sent by their mother, who is about to leave for New Zealand, to live with their grandmother in the countryside, like when they where kids. When BB meets Mint, her ex boyfriend when she was a teenager, she finds him very grown up; former motorpunk in the past, he is now fully dedicated to his garden. Also BB changed through the years; she's now a famous net idol and she denies the time when she was a rebel teenager. Despite having a boyfriend, the closeness with Mint leads her to reconsider her feelings. At the same time, Bambam meets again Beau, a childhood friend who has always had a secret crush for her.