Detectives from Class 4 A. Pterodactyls and Pushkin

The detectives from 4 'A' have adventures every day! What do pterodactyls dream about? How to avoid quarreling over a particularly valuable chocolate? Where has detective Krutikov gone? Where did the internet go wrong? What to do if your teacher is Pushkin, and where has beloved Mary Pavlovna disappeared to? Most importantly, the detectives have to solve the case of the missing happiness!