"Okay, you'll get the million." Bo can't believe his ears. What did Dad just say on the phone? Who was the mysterious caller? What million was he talking about? Overhearing a call by chance puts Bo and his friends YoYo, Simon and MM on the trail of a blackmailers' gang. With ingenuity and courage they get closer and closer to uncovering the criminals' secret. What they don't realize is that the noose is tightening around them as well.

Ulrich Renz was born in Stuttgart, Germany, in 1960. After studying French literature in Paris he graduated from medical school in Lübeck and worked as head of a scientific publishing company. He is now a writer of non-fiction books as well as children's fiction books.