The Emerald Forest was colourful and full of singing birds. Every day it resounded with the laughter of Mila and Frank, who loved to play hide and seek here. One morning, the sun was shining exceptionally bright and dewdrops fell from the leaves like sparkling beads. Mila, with her red ponytail and blue pea cap, was running through the forest clearing. Franek trotted behind her with a rucksack full of jam sandwiches. Suddenly, Mila stopped because something twinkled under an oak tree. Franek looked over to where Mila was looking. There was a folded leaf lying between the roots, tied with a green ribbon. Mila picked it up very carefully. They both looked at each other with wide-open eyes. The envelope bore the inscription: "For those who have the courage to look." - Who left this? - whispered Franek. - Perhaps fairies? Or forest spirits? - Mila was very excited. She carefully untied the ribbon. Inside was a map with strange signs drawn on it: arrows, dots, and a big X at the end. Next to the map was another short poem: "If you laugh often, And you have an open heart, Set out following the clue - Something unknown awaits!" Mila and Franek looked at each other. All around them, the forest seemed suddenly more mysterious. The birds had quietened down and something moved very quietly behind the bushes. Should they go where the map led? Would they discover what lay beneath the X? Just then, a shadow leaned out from behind a tree, and a soft sound rustled in the branches....