In Lausanne, the aspirant pianist Jeanne Pollet has lunch with her mother Louise Pollet, her boyfriend Axel and his mother. Lenna leans that when she was born, a nurse had mistakenly told to the prominent pianist Andre Polonski that she would be his daughter. Andr has just remarried his first wife, the heiress of a Swiss chocolate factory Marie-Claire "Mika" Muller and they live in Lausanne with Andre's son Guillaume Polonski. Out of the blue, Jeanne visits Andre and he offers to give piano classes to help her in her examination. Jeanne becomes closer to Andre and sooner she discovers that Mika might be drugging her stepson with Rohypnol. Further, she might have killed his second wife Lisbeth.