Banggwahue

Soo-Hyun is an ordinary middle school boy who lives alone and has long hair. He enjoys going out to play after school with Jun-Hwi, who sleeps a lot, and Jeong-Hoon, who is shy. One day, he skips his usual after-school class to go out to play. Contrary to what he thought would be an ordinary day, he gets caught up in an incident...

(Source: Lezhin, translated)

Note: Includes two extra chapters.