 After the death of his second wife, concert pianist André Polonski remarries his first wife, Swiss chocolate-company heiress Mika Muller. Soon a young piano student, Jeanne Polet, gets the idea that she may be André s daughter. She visits his house in Lausanne, gets to know André s son Guillaume who was born on the same day as she, and starts taking piano lessons from André. Mika Muller keeps serving them her famous hot chocolate, but with some help from a boyfriend conveniently working in a lab owned by Jeanne s mother, it soon becomes obvious to Jeanne that the chocolate doesn t come straight from the family company s production line.