Four inseparable friends look enchanted at the top of the hill, where twenty stone pillars have stood since time immemorial. Indeed, today, in front of the eyes of the entire town, the twenty-first stone will return to their circle, and one of the oldest man-made structures in the world will regain its original appearance. But what is it? Amid the screams of a frightened crowd, a giant boulder falls from above, and a mysterious man in a flowing cloak pronounces the words of an ancient spell: the stone circle cannot be completed, otherwise terrible, ominous, dark forces will break free. Of course, it is not proper for young archaeologists to take primitive superstitions seriously, but... it is from this moment that their lives turn into sheer chilling horror. The silence of the winter twilight is broken by heavy stomping, and a huge black dog with red glowing eyes...