The series, based on a sequence of novels by Edgar Wallace including a 1905 novel titled The Four Just Men, presents the adventures of four men who first meet while Allied soldiers in Italy during the Second World War, tasked with the dangerous job to blow up a bridge behind enemy lines.

In England in 1959 the men are contacted by telegram by their commanding officer, Colonel Cyril Bacon.

They operate from different countries: Jeff Ryder is a professor of law at Columbia University in New York City, Tim Collier is an American reporter based in Paris, Ben Manfred is a crusading independent MP who works from London, and Ricco Poccari is an Italian hotelier based in Rome.

Each character had an assistant: Guest stars included Judi Dench, Alan Bates, Leonard Sachs, Patrick Troughton, Donald Pleasence, Richard Johnson, Ronald Howard, Basil Dignam, Roger Delgado, Fenella Fielding, Charles Gray, and Frank Thornton (who appeared in more roles than anyone else).

DD = Dan Dailey JH = Jack Hawkins RC = Richard Conte VS = Vittorio De Sica Network released the 39 episodes on August 13, 2010 in a five-DVD Region 2 set.