The Man Who Knew Too Much (1956)

While vacationing in Morocco, the McKennas encounter a mysterious Frenchman, Louis Bernard, who warns of an assassination plot in London. When their son is kidnapped, they're silenced from alerting the authorities. In London, they uncover clues pointing to a bigger conspiracy and realize that an extremist group is involved. Racing against time, they delve deeper into the mystery, facing perilous challenges along the way.