Among the disastrous swamps, in the mansion of the entrepreneur Barskov, a frog meat merchant, terrible things are happening. Anna Somova, who has the ability to fight evil spirits, is the last hope of the unfortunate businessman. And in the mansion, as in the entire area, it is truly unclean. A couple of centuries ago, as Anna finds out, an innocent soul was killed here, so these places are cursed. The forces of evil dominate them... Anna tries to fight, but Barskov cannot be saved. He... shot himself on his birthday. Death approaches Anna herself. And then, having saddled a black horse, she rushes for help to the old hermit who lives in the swamps...