In the far north, where the mountains reach to the sky and the sea sings in the evenings, there was a Viking village called Fjordholm. In this village lived a small, curious Viking named Bjorn and his best friend Freja. They both loved adventures and invented new games every day. One morning, when the sun was shining exceptionally bright, Bjorn heard a story from his grandfather about a great enchanted horn that once belonged to a sea giant. The horn was lost many years ago, and whoever finds it can hear the voice of the sea itself! Bjorn looked at Freja, and courage shone in her eyes. "We must find him!" - she said enthusiastically. So they packed rusks, a piece of cheese and small wooden boats made by Bjorn's dad into their rucksacks. They said goodbye to their parents and set off deep into the forest, where huge green ferns grew and pinecones rustled underfoot. On the way, they met a fluffy squirrel who led them to a hidden stream. There, between the stones, they found an old wooden boat. It looked very old and was all overgrown with moss. "Maybe this ship once belonged to a giant?" - Bjorn asked. Freja mused, but before she could answer, a strange sound came from the bushes, as if someone was playing a very large horn. The children looked at each other in surprise. The sound repeated itself, louder this time! Bjorn and Freja moved slowly, holding hands. They walked deeper and deeper towards the sound until they stood in front of a large cave hidden among the trees. Inside, there was semi-darkness, and echoes spread through the walls. The sound of a horn resounded once more, just before they entered the cave.... Bjorn took a step forward, and Freja squeezed his hand tightly. What could be hiding inside? And was the lost horn of the sea giant really waiting for them there? Their hearts beat fast as they stepped inside....