The story of Pierluigi Torregiani, a Milanese jeweler who in 1979 was killed in revenge by the Armed Proletarians for Communism after killing one of their own during a robbery.

Convict Umberto is allowed to work outside prison during daytime as a librarian. There he falls for a beautiful woman who mistakes him for a volunteer helping the inmates — however, like a modern-day Cinderella, every day he must leave and be back to his cell before midnight... will they manage to live happily ever after?