All traffic comes to a standstill. What has happened? What's going on up ahead? calls a little boy on his tricycle. The road worker next to the "Caution: Traffic Jam" sign doesn't know. And now everyone is on the move: on roller skates, with a unicycle, a scooter, a skateboard, a buggy, or in a wheelchair: everything with wheels is involved. This way, you get to know fifty vehicles and their owners, some of whom are terribly annoyed (like the driver of the concrete mixer) or quite happy (like the children on the school bus), leaving their taxi behind or zooming past the traffic jam on a police motorcycle. But what has happened? A sensation: A dino has hatched from its egg! What a surprise!.