8th grader Stas, who ended up in the hospital after an accident, sees a ghost in his room one night. And before that, for several nights in a row, he had an amazing dream about an ancient Russian city, very similar to his native Koshkovo, whose inhabitants selflessly repulse the attacks of vile evil spirits, reminiscent of computer monsters in appearance. The young man begins to think that the ghost is somehow connected with strange dreams and, little he is trying to ask Stas for help.