Leo always thought that brushing his teeth in the morning was the most boring thing in the world. But on this ordinary Monday, something happened in the bathroom that he won’t forget for the rest of his life. His little sister Zosia, with toothpaste on her nose, noticed that a strange, swirling shape appeared in the mirror. ‘Wait, Leo, can you see it?’ she whispered. Leo rubbed his eyes. He collided with his own reflection, which suddenly blinked differently from him! Suddenly, the wall behind the medicine cabinet began to shift, revealing a spiral staircase leading somewhere deep beneath the house. They couldn’t say no to such an adventure. They took their toothbrushes – just in case – and carefully made their way down. Shimmering threads resembling toothpaste dangled from the walls. Suddenly, a bubble-covered figure emerged from the darkness. ‘Welcome, Guardians of Purity! A mission of exceptional importance awaits you…’ said the mysterious being, waving a large brush. Behind it stretched an entire underwater city made of shells and the teeth of sea monsters. Leo clenched the toothbrush in his hand. ‘What’s the mission?’ he asked, although he felt a slight tingle of fear and excitement. The creature looked them straight in the eye and replied: ‘You must save us from the menacing Plakul, who sneaks in at night and turns our pearly teeth into black stones! But first you must find the Lost Paste of Power hidden in the Labyrinth of Gums…’ Zosia grabbed her brother’s hand. A dark, winding corridor opened up in front of them, and mysterious sounds came from within it…