Bibi really loves the adventure stories featuring Prince, the clever super-poodle. Although Barbara has forbidden it, Bibi makes Prince come alive so that he can help her with her math. At first everything seems to go smoothly, but then it turns out that the robber Catgold has also come to life out of the book and is stealing from the citizens of Newtown. The worst thing is: he has his eye on a golden suit of armor in Newtown Museum. Bibi, Johnny and Prince want to set a trap for him. But it isn't so easy to catch Catgold in the act. In the end Barbara Blocksberg has to come to their rescue!