When an actor steps behind the camera, there is a built-in curiosity value to his venture, epsecially when a) he's a famous actor and b) he only ever made one such attempt. Sadly, "The Lost One" is not the buried treasure one might hope it would be. As a director, Peter Lorre doesn't do much that's cinematically inventive, and what's worse, he doesn't make much of the proceedings clear enough. And as an actor, he underplays to perhaps an excessive degree. With that said, this film does contain a couple of effective sequences, most notably a murder set in a train, and the final shot. ** out of 4.