Adaptation of John Gay's 18th century opera, featuring Laurence Olivier as MacHeath and Hugh Griffith as the Beggar.

While sailing lawfully up the Yangste in 1949, the British warship Amethyst found its return to the open sea blocked by Communist Chinese shore batteries that unexpectedly opened fire. In charge, Lietenant Commander Kerans was not however prepared for his crew and his ship to remain as a hostage for the Chinese to use as an international pawn.

American scientist Dr. Frank Smith is brought to Britain to help the C.I.A. There is a defecting East block scientist they want him to debrief. The commies are less than amused and set Dr. Smith up for a murder.