Nash, of course, was a real person (despite several liberties taken by the filmmakers) whose film persona only imagined that he was involved in top-secret government work, while Jericho is a fictional character set against the very real story of British cryptographers struggling against enormous odds to develop a machine that could break the Nazis' infamous Enigma code. The ultimate success of the British in this undertaking constitutes one of the most exciting noncombat exploits of World War II.
Apparently, watching a group of mathematicians thinking, while linguists scribble on bits of paper and engineers clamp widgets on rotors, isn't considered the stuff of high drama, however. So, rather than present a straightforward docudrama of the real Bletchley Park (a compound northwest of London, where British scientists and intelligence services were sequestered during the war), the filmmakers turned to Robert Harris's 1995 novel Enigma, which spices up the inaction with a love story.
As the film opens, Jericho, who was instrumental in cracking the first Enigma code, is returning to Station X (Bletchley's code name during the war) from Cambridge, where he went to recover from a devastating love affair with a Bletchley colleague, Claire Romilly (Saffron Burrows, always impossibly leggy and unattainable). He has been called back because the Germans, possibly tipped off by a traitor within Bletchley, have changed the code, and the Allies must figure out how to decipher the new one before an American convoy is set upon by German U-boats.
Upon his return, Jericho learns that Claire has disappeared, and he begins to suspect that she may be the traitor. With Claire's frumpy but game roommate Hester (Kate Winslet, who makes any character interesting to watch), Tom sets out to unravel the mystery of Claire's disappearance. Needless to say, the film's title refers to both riddles.
Making things more difficult for Jericho is a slick British secret-service agent with an insinuating manner and a perpetual sneer (Jeremy Northam, bloody marvelous as always), who keeps sniffing around, half-convinced that Tom may be the quisling.
Scottish actor Dougray Scott, unrecognizable from his earlier stints in Mission: Impossible 2 and Ever After, scores a bull's-eye as Jericho, conveying a convincing intellectual acumen as well as a sense of deep emotional vulnerability (the latter helped immeasurably by his thick lips, disheveled hair, and hooded eyes, which combine to produce an irresistibly sexy, wounded expression). That Jericho proves as adept at dissecting the riddle of Claire as he does the intricacies of the German code stretches credulity, but that's what happens when a script puts the demands of romantic intrigue ahead of every other plot consideration.
The actual events that took place at Station X in the 1940s would seem to be sufficiently fascinating not to require a silly old romance, but without the romance, the filmmakers obviously were concerned that no studio would be willing to make the film and/or that even if some studio did, no one would pay to see such a cerebral and technically demanding movie. Well, the filmmaking team, which included director Apted and producer Mick Jagger, was half-right. The movie got made, but the technical explanations are impossibly difficult for a lay person to follow (screenwriter Tom Stoppard probably understood it all and forgot he had to write for the rest of us). Certainly, a terrific sense of urgency underlies the story, and Tom's desperation over Claire is palpable, but that may not be enough for viewers who actually like to understand how the riddle is unraveling.