Victor, Lena and Maks were spending a boring afternoon at school when suddenly they heard an unnaturally loud buzzing from the teachers’ bathroom. At first they thought it was some kind of joke. But then Victor noticed that the shower door was slightly ajar and a blue mist, smelling of mint, was coming from underneath. All three of them glanced at each other suspiciously – after all, just yesterday at break they had been talking about the mysterious disappearance of toothpaste from the changing room. ‘I guess we’ll have to check it out, otherwise I won’t sleep,’ whispered Lena, adjusting her headband. Maks sighed nervously, but went in first. Victor closed the door behind them. Inside, instead of the usual shower, they saw a giant toothbrush leaning against the wall like a knight’s sword. Miniature, shiny capsules were spinning on the ceiling, looking like balls of fluoride from advertisements. More strangely, a loud buzzing sound was coming from the sewer side. ‘It’s… impossible,’ whispered Lena. ‘After all, our school is as boring as last year’s rusks!’ Suddenly, a moving tile slid out of the wall and a tunnel under the floor appeared. There was a strong smell of mouth freshener, and inside one could see traces of… teeth? ‘Someone here really cares about hygiene too much,’ joked Maks to lighten the atmosphere, although everyone felt shivers down their spines. Wiktor, unable to resist, took out the torch on his phone and shone it deep into the tunnel. They saw what looked like a maze of wires and slits. Something silver glinted at the end of it. And then they heard the sound of someone brushing their teeth… with a very, very large toothbrush. ‘Do we decide to go in, or do we run away?’ Lena asked, and both fear and excitement could be heard in her voice. Suddenly, a shadow jumped out of the shadows, resembling… a huge mole composed of toothpaste. It held an old toothbrush in its paws and hissed warningly. The three friends froze in stillness, wondering what to do now…