A faithful filmization of the play by William Gillette, Secret Service stars Richard Dix as a Civil War espionage agents. Dix is dishonorably cashiered from the Union army, but this is a ruse to allow him access to Confederate secrets. Shirley Grey plays the daughter of a Southern general who falls in love with Dix. When duty takes second place to romance, the Northern spy ends up in a Southern stockade. Like most of William Gillette's plays, Secret Service concentrates its action highlights in the second act, with the final scenes weighted down by illogical plot twists and the endless exchanging of "vital letters". The 1931 film is watchable, but reportedly not as visually stimulating as the silent version of 1919, which starred Robert Warwick in the Richard Dix role.