Hoping to spend a pleasant evening in a narrow family circle, Vikenty and his wife's sister Milana arrive at a country house. To their surprise and alarm, they do not find the hostess in the house, but they see brown spots on the floor that resemble blood...The police are withdrawing from the investigation under the pretext of "no body, no case"!The husband and sister of the missing woman decide to look for her on their own... They encounter a series of mysterious events and begin to suspect each other... in the disappearance of the Research Institute...