The Maria Skłodowska-Curie School in Zielona Dęba had always seemed like a predictable place to Alicja - lessons, tests, breaks and the slow rhythm of everyday life. But on this evening, when she stayed with her friends - Arek and Zuza - to prepare a paper on oral hygiene, things began to look different. All three of them were sitting in the now deserted chemistry lab. Amid test tubes, microscopes and cabinets cluttered with mysterious containers, they were testing various toothpastes on pieces of real shark teeth that the biology teacher had brought in as an experiment. Alice turned one of the old cupboards upside down in search of a model of a jaw, but came across something unexpected - a tiny, dusty jar labelled in Latin: "Dentis Lux". - What is this? - she asked, lifting the lid. A light, minty scent wafted from the jar, and the lamplight reflected off something inside, like a crystal. Arek smiled slightly, trying to defuse the atmosphere: - Maybe it's the secret ingredient in the world's best paste? Zuzka reached for her chemistry textbook, searching for the Latin meaning. - 'Toothlight'... It sounds like something out of a fantasy. At the same moment, the lights in the studio began to dim and blink. Somewhere from behind the door came a quiet murmur that could not be mistaken for a draught. Alicia had the impression that something or someone was waiting just behind the glass. Arek, with his usual courage laced with curiosity, went to the window and looked out into the empty corridor. In the silence, a soft crunching could be heard, as if someone was chewing something hard.... - I think someone is playing with us - whispered Zuzka, squeezing the jar tighter and tighter. Suddenly, the light went out completely. The studio was engulfed in darkness, and in this darkness a pale, phosphorescent light flashed in the middle of the table. The jar of "Dentis Lux" began to glow brighter and brighter, and the cool smell of mint appeared all around. As the three friends held their breath, a chill pierced the air and something unknown began to slowly emerge from the shadows, heading straight towards them....