If you, like Tolka Lapteva, happened to be born on the thirteenth, and besides, you turned exactly thirteen years old, rest assured: there will be some surprises. But for this to happen... And it all started with the fact that in a pile of gifts the birthday boy discovered a computer game with the terrible name “Monsters”. Burning with impatience, Tolka inserts the disk into the computer, and... And he becomes convinced that it is not for nothing that the number “thirteen” is considered ominous...