National Forensic Service (7)

The halls of Gangnam High School echo with the ghosts of adolescence past. It's been over a decade since Eunji and Sung walked these corridors, but I can almost hear the phantom chatter of students and the slamming of lockers.

I'm here during summer break, the building eerily quiet. The current principal, a middle-aged woman named Ms. Park, eyes me warily as I explain my purpose.

"Sung Ilyong and Kim Eunji?" she repeats, frowning. "I'm afraid I wasn't here back then. Let me see what I can find in our records."

While she searches, I wander the halls, studying faded photographs of past graduating classes. In one, I spot Sung – young, handsome, surrounded by friends. His smile is confident, almost cocky. My eyes scan the photo, but I can't find Eunji among the sea of faces.

Ms. Park's voice pulls me back. "I have their files here," she says, gesturing to a pair of thin folders. "Sung was a senior when Eunji transferred in. He graduated a few months later."