Far to the north, in a small village hidden between snow-capped mountains, lived a Viking named Olaf. Olaf was the youngest villager, but he had the biggest imagination and was never bored. One morning, as the village was waking up, Olaf saw a glittering footprint stretching across the frozen lake. He was sure it was not left by any man or animal he knew. Excited, he ran to fetch his friends, Astrid, who was quick as the wind, and Tor, who had the best sense of smell in the whole village. Together they got into a small wooden boat and sailed through the icy water to see where the luminous trail led. Along the way they passed icebergs and floating ice floes. Olaf told stories about dragons, mermaids and hidden treasures. Everyone laughed and guessed if they were really going to meet something unusual. At one point, the boat began to rock slightly and the water in front of them shimmered blue. Suddenly, a large, sparkling shell emerged from the ice.... The children held their breath. What was hiding under the ice? Was it the dragon from the legends that was said to reside in Winter Bay? Or was it something even more incredible? Olaf squeezed the oar tighter, and Tora and Astrid looked at each other with wide-open eyes....