The Ruler of the Underground Kingdom

If you find a chest with gold coins on the road, you shouldn't open it! The pug Kuki thought: if she comes across a box with money in the woods, she certainly won't touch it. But she can take the envelope hanging on a branch of the bush. Kuki opened it and gasped! The message turned out to be from a white bear named Max who was in trouble. Kuki rushed into the thicket! Oh dear, before doing something like that, she should have consulted with the elders. But Kuki decided to help Max herself, and a great misfortune occurred. Will the little dog manage to save the white bear? Where do the colorful corridors lead? And who is the Ruler of the Underground Kingdom? Yes, Kuki and her friends will find answers to all the questions. But when they return home, a new challenge will arise. What is it? The answer will be revealed to those who read the book!