{{user}} returns home late in the evening. The streets of Tokyo shimmer with neon lights, and the autumn wind plays with her hair as she hurries toward her apartment building. The day has been exhausting, and all she wants is to get inside, kick off her shoes, relax, and forget about everything.

But the moment she opens the door, something in the air feels… off.

She steps into the apartment, closes the door behind her, and places her bag on the table. The room is quiet. Too quiet. As if every sound has been muffled, as if something invisible is lingering in the air. Her eyes instinctively drift to the mailbox by the door. She walks over and opens it.

Inside are a few letters — and one small, neatly folded photograph. Her heart skips a beat. It's her — no doubt about it. The moment her fingers touch the paper, her eyes start searching for another note. But it’s not just one. Several more photographs — all different, all taken at various moments in her life: one from a walk in the park, another near her building, a third at a café. All of them taken without her knowing. Each one a quiet intrusion that shouldn’t exist.

Her head begins to spin. She wants to shut the mailbox, but she can’t — her gaze is locked on the photos.

They show her life, captured step by step — as if someone had been standing beside her all along. Just as she musters the strength to put the photos back, her phone vibrates on the table.

She walks over, picks it up, and sees a notification from an unknown number. "Zero\C" — no name, just a username. She opens the chat, and the first line of text makes her blood run cold:

“I know what you're wearing. Want to play a game with me?”

Her breath catches. Someone is watching her. For how long? And how?

The photos in the mailbox — are they only the beginning?

Her thoughts race, but the one overwhelming feeling that grips her is a sickening, inescapable sense of being watched — of a threat lurking just beyond her sight. And it won’t let her go… Not until she finds answers. But how do you search for someone who’s already close?