The Colourful Circus has come to town today. Tom and Lena stand in line with their mum. The big tent glows with lights, smells of popcorn and candyfloss. A drum and a whistle are heard, Tom's heart beats faster. A Circus Master in a red waistcoat enters the arena. "I'm looking for a helper!" he calls out and shows the tickets with a star. Tom's ticket has a star, so he walks up to the railing. The clown Koko waves, the magician Hat winks at Lena. The gentleman leads Tom behind the curtain and whispers. There's about to be a big number, you need a brave finger. Under the table stands a box with the number three and a golden padlock. The lid trembles as if someone is tapping from inside. Next to it jumps a tall hat and knocks over a small stool. A note lies on the lid: "Do not open before the signal." The drum beats once, a second time, the lights suddenly go out. Is this the signal already? The padlock itself slowly begins to move. Tom lifts his hand over the key and....