Very bad ghost. Book 3. Kayblinger S.

It seems that Poltergeist appeared on Redisina Street! This is not an ordinary ghost, but an evil spirit who loves to harm people. Dragomir ferocious (and this spirit is called that) is sure that the treasure is hidden in the garden - a gem that can make the ghost invulnerable. And the poltergeist is ready for anything to take possession of this treasure! Harry cannot help Otto, he cannot cope with such a strong ghost. Only one thing remains the boy: he must find the overlords of the poltergeist, special agents from the other world as soon as possible. The trouble is that these are very mysterious and very busy creatures. How to convince them to come to the rescue?