In the depths of the ancient city of Ercalon, where the narrow streets wriggled like silvery snakes and the glows of lanterns danced on the wet stones, lived three uncommon friends: Liris, the cartographer's daughter, Dariel, a young blacksmith who spoke steel, and Eno, a librarian's apprentice, perpetually read in old books about the world above ground. This city had never seen the sun - built underground, illuminated by crystals that dimmed once in a while, causing concern for all the inhabitants. For several weeks, the lights had been going out more and more often, and people whispered about old stories that the oldest people no longer remembered in full. One evening, as they walked through a market illuminated by the faint glow of phosphorescent plants, Dariel noticed a streak of light running through a crack in the tunnel wall. Siri, the old root vendor, hissed quietly: "This is no ordinary light. Someone summoned it." The friends looked at each other communicatively. Their curiosity was stronger than their fear. Following the mysterious glow, they passed through narrow passages and abandoned workshops until they came to a huge gate overgrown with lichen. Eno put his hand to a shallow indentation in its surface and suddenly the whole gate flashed with blue light. Drawings appeared on it: children running towards the light, an old man with a lantern and unfamiliar signs. From the dark corridor beyond the gate came their quiet chanting, as if someone was humming an old song they did not know, and a glow as brittle as ice penetrated slowly through the cracks in the walls. Around them, the air became heavier and the echoing lights danced on the wet stones beneath their feet. Dariel breathed deeply, Liris clutched the map in her hand, and Eno took a step forward when suddenly there was a deafening clatter just behind them, and the gate began to open slowly, revealing the arched shadow of a powerful figure....