Detectives of the North Sea. Book 3: Skeleton Kashalota

In the third book of the series, the parents of Lucas and Emma went on tour. Brother and sister love them very much, but still glad to live a few days of an independent adult life.
Finally they ended up in a whale museum, met the numerous inhabitants of the North Sea and saw the main exhibit-a huge skeleton of a real sperm whale (sperm whale, as you know, belongs to the subdivision of toothy whales) But what is it? The ribs of the sperm whale is fake! Some attackers steal a precious whale bone, replacing fragments of the skeleton with gypsum fakes. Emma and Lucas immediately started an investigation and quickly attacked a trace of a gang trading in a whale bone. These are the colorful characters of Dylda and the pocket, as well as their boss of the switch.
Having carefully studied the “Guide for Real Detectives”, which was inherent in his brother and sister from a cousin, the children fearlessly went in pursuit of scammers. It’s good that they took with them a set of master keys from grandfather’s detective suitcase, otherwise they would have to sit at night in a locked whale museum.
At some point, luck changed the young detectives, and they fell into the hands of the bastards. But the ingenuity and absolute composure helped Lucas and Emma this time. Even gags and tied hands are not a hindrance to real detectives. They managed to free themselves and cunningly left the mark that brought the police directly to the den of criminals.
The book is read in one sitting thanks to a famously twisted plot, interesting details of the investigation and an excellent translation of Pavel Frenkel