Leon lived on the edge of the Rainbow Forest, where the trees were red, blue, yellow and pink. Every morning he would wake up with his friend, Figa the cat, to admire the colourful leaves and the singing birds. One day, as they ran out into the yard, Leon noticed something strange. The tree in front of his house had turned quite grey! - Fig, can you see it? - exclaimed Leon. - Where did the colour disappear to? Figa murmured quietly and looked towards the forest. The further they looked, the more the trees were grey. Even the grass had lost its green glow. Leon felt a small ball of anxiety, but also curiosity, grow in his stomach. - 'We have to find out what's going on,' Leon said firmly and set off towards the Rainbow Forest. Fig ran right beside him. They wandered along a path full of disappearing colours until they reached a clearing where the oldest and largest tree in the forest grew. There, under its grey boughs, they saw.... something very unusual. Leon stopped, and his heart beat faster. Someone - or something - had just been moving around the trunk, holding a small, shiny jar in its paws....