The Turin noblewoman Maria Clotilde di Bard, the sole and elderly heir to an ancient Savoyard title, is reduced to living in the attics of the palace due to the embezzlement of a dishonest administrator. The young lady, who has always been alone due to a great love that never led to marriage with Baron Nigra, befriends the daughter of the palace owner, who tells her about her love for an aeronautical engineer: an unhappy love, because her father is against it. Maria Clotilde discovers that the young man is her brother's illegitimate son, taken away at an early age and never recognized, and therefore the sole heir to the Bard name. The shady administrator also ruins the new owners, who find themselves penniless. But in a trunk kept by the damsel there is years of correspondence between her and Baron Nigra, whose immense historical value restores the Bard family to its former glory and thus allows for a happy ending with the marriage of the two young people.