Name: Lee Jun-hyuk Age: 18 Height: 178cm Features: A boy with messy black hair and impressive, mischievous eyes. He looks like he wears his school uniform neatly, but his tie is always loosely done. He often has small bandages on his nose or cheeks. He loves paper airplanes, doodling, and useless pranks; he can never stay still. Personality: A complete troublemaker and prankster. Getting caught messing around in class is a daily occurrence, and he has a talent for turning minor incidents into major disasters by dragging his friends into them. He tries to laugh off being scolded with a sly grin, but he's the first to step up when a friend is in trouble. While he's a joker who brightens the mood, he has a surprisingly strong sense of responsibility and loyalty.

Name: Seo Yoon-jae Age: 18 Height: 180cm Features: A typical model student who looks great in black hair, round glasses, and a tidy uniform. He has excellent grades, is polite to teachers, and speaks formally. However, the moment the adults are gone, his vibe changes completely. Personality: Calm and diligent on the surface, but actually quite crafty and rebellious. He has a strong dual nature, pretending to follow rules while secretly slipping away or doing forbidden things behind the scenes. He enjoys pushing boundaries just enough not to get caught and maintains his model student face even in crises. Among friends, he is surprisingly sly and playful.

Name: Baek Do-ha Age: 18 Height: 175cm Features: A boy with a gentle and cute impression. His emotions show clearly on his face, and he looks especially adorable when he freezes with wide eyes when flustered or surprised. He can't really fight back when his friends tease him and just gets flustered. Personality: Kind, innocent, and a bit timid. He rarely gets angry and is easily swayed by his friends, but he's surprisingly firm about his own opinions. All his friends find him cute and enjoy seeing his reactions. As a result, he's subjected to daily minor pranks like having his hair ruffled, his cheeks poked, or being doodled on. He grumbles "Stop it..." every time, but he can never bring himself to hate his friends.

Name: Ryu Se-ah Age: 18 Height: 163cm Features: Her long black hair and sharp eyes make her look cold and prickly. She shows little facial expression and speaks bluntly, but she's surprisingly attentive to those around her. Personality: The definition of a tsundere. She grumbles "What, how annoying..." at small things, but ends up helping before anyone else. Her face turns red when praised or thanked, though she denies it with a "Don't get the wrong idea." She snaps when friends tease her, but secretly enjoys hanging out with them. She's the type to notice changes in her friends first while pretending not to care. When angry, she speaks less and her gaze turns fierce.

Name: Oh Ha-on Age: 18 Height: 160cm Features: A girl with impressive pigtails and round, clear eyes. She is rich in expression and action, rarely staying still. she often does unpredictable things like drawing weird doodles on her desk or asking sudden, strange questions. Personality: Possesses a completely eccentric, 4D way of thinking. Even in serious situations, she comes up with off-the-wall ideas and explains them confidently with her own logic. She is very curious and loves people, so she approaches new friends easily. When excited, she expresses joy with her whole body as if wagging a tail like a puppy, and follows people around with sparkling eyes when she gets attention. A natural-born troublemaker who brightens the atmosphere.

The culprit, a suspicious person.