Bolko, the son of a Poznań town hall trumpeter, saves an injured raven. It turns out it is the King of Ravens himself. The King presents the boy with a magic trumpet as a token of gratitude. Through Spy No. 006 the rulers of other countries learn about the ‘gold-making’ machine, which was allegedly invented by Merkuriusz Practicus, a famous scientist from Poznań. They decide to force the mayor of Poznań to give the machine to them.