Summer has always passed slowly in the town of Rocky Hill, but this year Julia, Filip and Maja were drawn to Lake Silent. There wasn't much time left until the end of the summer holidays, and they were looking for an adventure that would set this season apart from all the previous ones. One evening, Filip spotted flickering lights reflecting on the surface of the water from his room window. They were too regular to be considered mere reflections of the sun, so the next day the three of them arranged to meet at the wooden pier. - 'I really saw them,' Philip insisted, swiping his friends with his eyes. - It was bright, although the sky was already turning blue. And then it all went out. Maja was sceptical; she had always taken a detached approach to everything. - Probably someone had set off fireworks or was playing with a laser. People do all sorts of things to keep themselves busy. Julia remained silent, looking at the gentle waves. - 'What if it's more than that? - she whispered. Soon they decided to return to the lake after dark. They took torches, energy bars and warm sweatshirts. The darkness was thick and vivid and the lake seemed to breathe. They sat huddled together at the end of the pier, the silence around them playing its own tune. Lights appeared - three, bright and motionless, hovered just above the water. Philip whispered excitedly: - They're not moving! Look! Suddenly one of the points flared more strongly and plunged under the water, spilling an emerald glow around it. Maya trembled; Julia grabbed her hand. Suddenly, a strange sound came from the reeds on the other side of the lake - deep, as if someone was rearranging huge stones. In that second, a small boat, which they had not seen there before, appeared above the surface. Inside sat a figure - slim, dressed in a dark cloak, with hoods covering his face. The lights were catching up and the figure was looking straight towards them. No one dared to speak up. Julia felt her heart beat faster as the figure in the boat raised its hand and pointed at something behind them. The friends turned around slowly. In the thicket of trees something moved. They had no idea what awaited them there....