The Secret of the Brown Ampoules

A friendly company - Asa and Matilda, Kostya and Marat - has been given a new case. But not just any case, as they don't have any other kind; they are real detectives, and they have a private investigation bureau "Quartet"! The guys have to deal not only with the explosion of a car but also with the mysterious abduction of its owner! And the most interesting part is discovering what these ampoules with the brown substance are...