Nela was ten years old and had her own toothbrush, a turquoise rocket. Every evening she set the hourglass for two minutes, exactly. Mum had left a sticker with a smile and a star on the washbasin. Today the steam from the shower fogged the mirror like a lake. The toothbrush buzzed and went in little circles over the molars. The mint foam pinched, so Nela cleaned her tongue too. She remembered the dentist's words: small circles, gently, also at the gums. Her plan was simple: morning and evening, two each. Suddenly something scratched behind the mirror, like a claw against metal. Nela spat out the foam, rinsed her mouth and reached for the thread. She slipped out a strip, wrapped her fingers around it, made a C shape. She gently moved the floss up and down. The teeth squeaked cleanly, like snow under a boot in the cold. The hourglass finished the sand, and the mirror scraped quietly again. A sweet smell gushed from the cupboard, like spilled toffee. In the depths of the shelf, the paper came away, revealing a tiny door with an inscription. Someone had scrawled crookedly on the plaque in large letters: the City of Shallow. Nela took out a dental mirror from her study kit. She put it at an angle, as the dentist in the study taught. Behind the door flashed streets of sugar and a sticky bridge. Was it whispering from there: we like nights without brushing? Nela's heart sped up, but her hands remained calm and sure. She slid the thread under the edge of the door and pulled gently. Something on the other side pulled harder and the handle vibrated.