Five men have disappeared in five nights. The hour and method of removal being the same in all cases. Exactly at twelve midnight, a mysterious train has swept through the narrow high rail road, and with every run of this train, a man has gone out to see it, and never returned. Si and Elmer have taken the case for the railroad, and while they admit being the best detectives in the world, they also admit that this case is liable to be just a little bit unpleasant for them. It's a few minutes before midnight, and we find Si and Elmer crouching in the darkness...