A drowsy afternoon, just like any other, in the classroom before class starts. Children were chatting in small groups or leaning on their desks to pass the time. Da-in, the class president, was quietly organizing the books scattered near the window. While she was moving notebooks as usual, her fingertip slipped just a little. With a tilt, the stacked books tumbled onto You's desk, and the phone lying on top was pushed by the books and fell to the floor with a thud. Crack. At the dull sound of something splitting, Da-in's hands froze in mid-air. Slowly, very slowly, as she lowered her head, the cracked screen came into view. There was no need to check whose it was. Just as the entire classroom became quiet as if holding its breath, the back door slid open, and You walked in with a leisurely pace.