Mitia Filin is only 13 years old, but he already has a detective agency. Filin was named Mitia due to the combination of his large eyes, nose, and last name, which means "owl". He loves to create conspiracy theories and takes on the most complicated cases. He is assisted by: Anya Volkova (who is involved in academic rowing and drinks black coffee too often, which slightly scares Mitia), Sergey Ivanцов (a disaster-prone person who speaks like a retired professor of paleontology) and Lena Filippova (the local "Google", an excellent student and class monitor who plays the guitar masterfully).
Four friends from one yard known throughout the city. The yard of the Five Houses, each with a front and a back entrance, attics, and steep staircases. And also in the Five Houses is the secret headquarters of Mitia Filin and his friends.
Together, they will catch a criminal who stole the secret diary of Emperor Nicholas II; find a unique stamp and a missing ancient almanac; learn what connects a world-renowned geneticist and their biology teacher; rescue a victim from kidnappers and even participate in a contest by Kirk Hammett, the guitarist of "Metallica".
"Nothing is as deceptive as too obvious facts," — Sir Arthur Conan Doyle, Sherlock Holmes, and Mitia Filin.