Franek and his little sister Maja were very fond of their tree house in the garden. One evening they decided to spend the night there. They took torches, pillows and their favourite teddy bears. When their parents said goodnight to them from the garden, the children hid in a soft blanket and started telling each other stories. Suddenly, just as they were about to fall asleep, they heard a quiet whisper just below the window of the cottage. "Ssssss.... who's here?" - said the little voice. Frank peeked through the glass and noticed a small spinning light floating straight towards them. Maja squeezed his hand in fear and whispered: "What could it be?" Then the light stopped right in front of the cottage door, and the whisper resounded once more, this time more clearly. The door slowly began to open....