In the heart of the green forest lived a badger named Boris. Boris was a very curious animal. He liked to explore new paths and see what was hiding among the bushes and trees. One morning he woke up earlier than usual because he felt that this day was going to be special. - Today I will go further than ever! - said Boris to himself, putting on his favourite striped hat. Boris set off through the forest, listening carefully to the birds singing. On the way, he met his friend Zosia the hare, who was just practising jumping over the moss. - Where are you going, Boris? - Zosia asked, hopping around him. - I'm going where none of us have been before! Do you want to come with me? - suggested the badger. Zosia was trembling with emotion. - Of course! They wandered off together and were joined on the way by Witek the squirrel. He came down from a tall pine tree because he heard his friends laughing. - 'You can't go without me! - he called out and was soon right next to him. The merry trio walked deeper and deeper into the forest. Suddenly a thick, fern-scented copse stretched out in front of them. Behind the copse they noticed a huge old tree trunk, under which there was a small hole leading straight underground. - 'I've never seen that here before,' Zosia whispered. Boris was the first to come closer. - It looks like the entrance to some kind of tunnel.... Do we dare to see what's inside? The friends looked at each other with wide-open eyes. What will they find underground? Would they meet the new inhabitants of the forest there, or encounter something unusual? They gathered their courage and began to cautiously make their way inside, when suddenly they heard a quiet rustling coming from the dark tunnel....