The scene of the story taking place in the 18th century is an inn, which is advertised by its owners for sale. The inn was namely the scene for mysterious disappearances and murders, but the result of all these events, the treasury is hidden and guarded by the mother. Everybody want to get it from her during one night: the inn-keeper couple, the fake couple who arrived as buyers, Colonel Majorossy with his son, the secret agent and the servants.