During a night game in the city, five friends break into an abandoned dental surgery and find a clue tied to the White Mask, but something in the dark corridor is already moving.
It was a warm June evening, the kind that made the city feel half-asleep and slightly unreal. In front of Kopernik Secondary School, Lena, Krzysiek, Alicja, Borys, and Maks stood in a tight circle around the map their organiser had handed them. They lived for urban riddle games, especially the ones built on old legends and bad ideas that sounded brilliant until the lights went out.
This time, the clue led them to the White Mask, a figure from one of the city’s half-forgotten stories: a guardian of teeth, braces, and perfectly polished smiles, said to haunt an abandoned dentist’s office on the edge of town.
Lena traced the route with her finger, grinning. She was the sort of person who could turn any empty street into a case file. "The last clue says the back entrance," she said. "And according to the rumour, that place still has teeth that move when nobody’s looking."
Krzysiek snorted, but his eyes were already searching the street behind them. "That is the worst sentence you’ve said all week."
They found the office crouched between two vacant buildings, its rusted sign tilted at an angle: Dr Anna Mint's Office. One of the front windows had cracked long ago, and the poster inside showed a smiling cartoon molar so wide it looked almost insulting in the dark.
Alicja pushed the side door. It opened with a soft, unwilling click.
Cold air spilled out, carrying the stale smell of antiseptic, damp paper, and something sharply sweet, like mint left too long in a closed drawer. Their flashlights swept over shelves lined with toothbrushes, half-used tubes of toothpaste, spools of floss, and sealed plastic cups that had turned cloudy with age.
Borys froze in the doorway. "Tell me that chair wasn’t there a second ago."
In the centre of the room stood a dental chair draped in white cloth. On the headrest rested a mask painted chalk-white, with two oversized incisors where the eyes should have been. Beneath it lay an envelope, weighted down with a metal instrument.
Lena stepped closer and tore it open.
Only those who care for their teeth will leave here smiling.
The sentence ended there, as if someone had stopped mid-thought.
Before anyone could speak, a sound drifted from the corridor at the back of the office. Metal scraping against metal. A soft, unmistakable giggle.
Maks turned off his flashlight by mistake. Darkness rushed in, thick and immediate. On the far wall, their beams caught fresh writing that none of them had seen a second before:
WHAT YOU HIDE UNDER YOUR TONGUE WILL BE FOUND TONIGHT.
Then something clicked in the locked cupboard at the end of the corridor.