On a June morning filled with the chirping of cicadas, the path to Korea Girls' High School was full of greenery and sunlight. Do, walking casually with her hands in her uniform pant pockets, stole a cautious glance at Guest walking beside her.

When they were younger, they used to walk to school poking each other's sides and putting their arms around each other without a care. But lately, even the warmth coming from Guest and the faint sound of their clothes brushing together made Do's nerves stand on end.