When Eight Bells Toll (1971)

Phillip Calvert is a British Treasury secret service agent assigned to stop the ruthless pirating of millions in gold bullion off the western coast of the Scottish highlands. His search takes him to the small port town of Torbay on the Isle of Torbay where numerous fishing boats, yachts and people have been mysteriously disappearing. A trail of deceit and subterfuge leads him to Cypriot tycoon and shipping magnate Sir Anthony Skouras and his beautiful wife, Charlotte aboard their luxury yacht anchored off the coast, who may hold the answers to the truth.