Cornelius Leyden (Peter Lorre) is a successful writer of detective fiction who is spending some time in Istanbul during 1938 when he hears of an intriguing event: a body washed up on the beach recently. Leyden is at a party when he gets to talking with a fan of his work, the local lawman Colonel Haki (Kurt Katch) , who regales him with the story of the dead man; he was called Dimitrios Makropolous (Zachary Scott) and was involved with a high level of international crime. Leyden asks to see the body out of curiosity, and regrets it, but this inspires a fascination in him to track down those who knew Dimitiros - perhaps there's a book in it...
There's a rich, moody atmosphere to The Mask of Dimitrios that almost but not quite papers over the cracks of its deficiencies, but those drawbacks are nothing to do with its cast. A bunch of seasoned character actors were hired to bring Eric Ambler's novel to life, and with Lorre and his frequent screen collaborator Sydney Greenstreet working at the top of their games, there was a lot of pleasure to be had simply watching them share scenes together. But therein lay the flaw as almost half the movie was taken up with flashbacks to Scott's devious villain, and you really did miss Lorre and Greenstreet when they were not there.
This is exacerbated by the fact that often the film seems like two stories edited to run concurrently as we switch between Leyden's investigations and Dimitrios's machinations and they appear to have very little influence on each other apart from offering Leyden someone to interview. And yet, although you would expect the flashbacks to hold the lion's share of the attraction, such is the charisma of Lorre and Greenstreet you'd much rather they teamed up sooner and the plot focused exclusively on them; don't underestimate the command these two had over the screen when they were together. They were powerful enough on their own, after all.
This duo were paired in a few films after their huge success in The Maltese Falcon, one of Hollywood's great "odd couples", and when the top-billed Greenstreet enters the frame, you sit up and take notice. He plays Peters, who takes a keen interest in following Leyden's sleuthing without explaining why - or why he frequently politely pulls a gun on the meek writer - but after a while a genuine sense of companionship develops between them that has quite some measure of charm. In contrast, during the flashbacks, in which neither of them appear, not even Peters, Scott plays the title character cold as ice, which may have been how it was written but doesn't leave you as engaged as you hoped you might have been.
Leyden travels across Europe amid some truly wonderful photography, meeting a collection of shady individuals who help to flesh out the plot. So after the encounter with the Colonel, who makes him think there could be a novel in this (the original Ambler work was purportedly based on a real person, a dodgy arms dealer in Eastern Europe), he hops on a train and meets Peters in the same carriage - and not coincidentally. That's not all, as he talks with an old Dimitrios girlfriend in a nightclub, who appears to have been deeply hurt by knowing him, and a gambler who details how Dimitrios became a master of espionage, all interesting people and making you regret the way the screen swims and we head off into another recollection when you'd rather hear them sit and talk. To compensate, the film does have an excellent ending which even if it doesn't successfully marry the two narrative threads, is memorable for all that. Music by Adolph Deutsch.