A mystery lies behind the door of apartment three at No.12 rue des Amants. This is a beautiful old apartment block, far from the glittering lights of the Eiffel Tower and the bustling banks of the Seine. Nothing goes unseen here, and everyone has a story to unlock. Between the watchful concierge, the scorned lover, the prying journalist, the naïve student, and the unwanted guest, who holds the key to this mystery?