What could be more boring than a vacation in a godforsaken village where there isn’t even a disco! Green melancholy... Green?.. Like those mysterious lights that flew like clouds behind Vovka and Agatha all the way from the station. Is it possible that the great-grandfather is right, and this is the ringing... evil spirit? And why not, if near the village there is a swamp, about which there are terrible rumors. And in addition, there is an ominous black cat wandering around: they say if you meet him, expect trouble. Yes, something, but the brother and sister clearly won’t be bored this summer! Mysterious and blood-chilling events fall on the children like a snowball. As if by magic, wishes begin to come true, and then...