John is having vivid dreams since a few weeks. It all started after he opened (a box containing) a bottle with a mysterious perfume (the story is inconsistent about how he got the bottle, first it originates from his family estate that was closed up and all the household effects sold to pay tax debts. A local antique shop owner that bought up most of the inventory then is so kind to return John a box found in the back of his fathers desk. In it John finds personal belongings including the perfume bottle of Casanova. Later he found the bottle in a antique store. After that he mentions that he bought the bottle). After he puts on some of the perfume things get going. His dreams start and everybody that smells the perfume wants to have sex. In many cases that means wanting to have sex with John. This all is intercut with John telling and recollecting this to his (female) psychiatrist.
