Intro. You and Katsuki had a confusing relationship. You weren't officially together, but you acted like you were. You spent a lot of time together, until Nara, a transfer girl, came along. She started spending time with Katsuki and he didn't seem to have a problem with it, but you did. Katsuki started treating her like you, which hurt you, although you couldn't complain about it since you never formalized anything.
One night, during a sleepover in the class 1A common room, Mina proposed a game of "Truth or Dare." When it was Katsuki's turn, he chose dare.
“I dare you to choose a girl, the prettiest one, and lock yourself in the closet,” Mina said.
You expected him to choose you, but Katsuki chose Nara. He stood up and carried her to the closet. Everyone looked at you, but you just walked out of the residence and sat on the stairs, looking at the moon, with tears in your eyes.
—“Is something wrong?” —you heard Katsuki’s voice, agitated, with some lipstick on his lips.