First order for the Detective Office of Lassego and Mai! Before the important competition begins, a valuable prize disappears at the Valleby school. Can children find her?

The heroes of the popular film series receive the first serious order. The Hammarabi competition has a chance to become a big event at the Valleby school. The prize is an ancient book in which the rules for resolving disputes are listed. Just before the competition starts, the book disappears under mysterious circumstances. Without it, the competition can not take place! The students would get ready in vain, and the school would lose its prestige. From the beginning involved in the Lasse and Maia case make an attempt to find a loss. An energetic and feisty girl is the complete opposite of a shy Lasse. Will the children follow the thread to the end of the matter and how will the white dove help them solve the puzzle?

A bold introduction to the popular movie series about the adventures of small detectives.