"I seek you, marvellous woman who will reduce me to chain. But do you exist? if you are there, replay to silver bird..." This is an ad appeared in a newspaper of erotic ads: "sex office". Xenia is an university researcher and brilliant mathematician with a complex and tormented personality and suffering from sleepwalking. One day she answers the ad of a young masochist named Ghost. They start to do some masochist games together until, the day after, she discovers that ghost is dead. She remembers nothing about the night they spent. She has to find Ghost's assassin: unless it's not, if possible, herself. Silver, Ghost's friend, starts looking for the assassin too. They "meet" all the people that have had some strange relation with Ghost. They are afraid of themselves and of each other; they have sex at Ghost's house, when somebody, probably the assassin, gets in, strikes Xenia and.