The first rays of the setting sun had already disappeared behind the futuristic dome of Smile Academy when Victoria and Kuba crossed the heavy glass doors of the main entrance. It was their first day at the two-week science workshop, which was hard to get into. The academy, located on the outskirts of the city, was surrounded by tall trees and a thick fog that drifted over the elegantly trimmed lawn in the evenings. They themselves weren't sure if it was more of a science centre or an elite boarding school from the future. In addition to them, the group included Pola, an avid lover of chemistry experiments, and Alan, the creator of viral health videos. They spent the first few hours exploring the state-of-the-art rooms - each with its own humanoid assistant who could tell stories about bacteria or act out interactive scenes about the disasters of not brushing teeth. The diagnostic lab looked like the deck of a spaceship, and stations awaited in the laboratory to assess the composition of the mythical 'fluid of life of enamel'. In the evening, by the light of the panoramic screens in the common room, they met Dr Ewa Nowacka - the director of the Academy. She quickly cut to the chase: "During this stay, you will have the opportunity to solve challenges that few have overcome so far. Oral hygiene isn't just about brushing your teeth - it's about learning how the world of microorganisms affects our daily lives." The next part of the evening was spent playing inclusive games. Victoria noticed that some of the doors in the main corridor were locked with digital locks. Alan, as befits an influencer, couldn't help himself: - I wonder what they're hiding in there. Maybe some NASA-tested toothpaste or 3D printers for teeth? Pola joked: - Or a laboratory where they clean sonic toothbrushes? They laughed, but curiosity grew. Night came faster than anyone expected. Once everyone was lying in their capsules - futuristic beds with touchscreens - Victoria heard a strange sound. Something like a steady hum, punctuated by a quiet click. At first she thought it was just the ventilation, but the sound grew and sounded more and more unnatural. She looked at Kube, who was clearly concerned. - Can you hear it? - he whispered. Victoria nodded her head. At the same time, a red light flashed on the panel by the door of their pod. After a few seconds, a message appeared: "Zone C - restricted access. Security level: 2.2". Alan couldn't contain himself - he momentarily pulled out his phone and started recording. Pola carefully slipped out of bed. Together they moved towards the door, which swung open barely perceptibly. Behind them stretched a dimly lit corridor, leading to a part of the Academy they had not been in before. They walked between tall bookcases full of toothbrushes and vials of strange coloured liquids. The sound became clearer and clearer - as if something or someone was moving in the darkness. As they stopped at a door marked 'Zone C', an unfamiliar rumbling sound came from inside and a blue light flicked on for a moment. They noticed footsteps on the floor that had certainly not been there before. Suddenly, the door itself began to open slowly and a cool gust of air hit their faces. Beyond the threshold waited something they had not expected to find....