Jana and Margosha are invited by their friend Rita Verbianskaya in a chic suburb near Moscow, surrounded by pine trees and almost cut off from the world by snows. The occasion is a wonderful one - the anniversary of the head of Rita, the president of the Samsonov holding. But fear and panic embrace the guests after the picnic was found hanging on the birch of the vice-president Dmitry Antonov. The investigation begins ... It turns out that almost all the guests at different times saw a mysterious female figure in a black hoodie with a huge hood, so that nobody could see the faces ... The ensuing series of murders and assassinations instills a mystical horror on everyone who has survived. The investigation comes to a standstill. Even detectives are a little bit of a rationalist-pragmatist ...