Sait-On Jamais? on AllMovie

Roger Vadim's second directorial project was Sait-On Jamais, which was released in English-speaking countries as Does One Ever Know and No Sun in Venice. Set in Italy, this romantic suspenser is inventively paced to the musical improvisations of the Modern Jazz Quartet. On a Venetian holiday, a French journalist (Christian Marquand) meets and subsequently beds a mysterious beauty (Francoise Arnoul). Before long, the journalist is mixed up with the woman's ex-lover, a neurotic hoodlum (Robert Hossein) in the employ of a depraved Austrian baron (O.E. Hasse). Greed rears its ugly head when the hood bumps off the baron while searching for the latter's hidden millions. It all ends in a thrilling rooftop chase at the baron's palatial estate.