Patricia's mother puts her in the hands of Vincent in order to give her a sex education. He is a married man who shares his life between his piano and lovely maids.Jeannette, the maid, puts her on the right track by having her witness the hot parties given by Vincent from behind a see-through mirror. On these events, all the women are dressed in black underwear. Things continue in that way until one evening when Patricia, dressed in black, gets through the mirror to join them.