The Civil War has just begun. The Southern states are seceding, and Maryland is torn between North and South. In Baltimore, a wealthy and influential shipping magnate named Elias Liberty is financing and assembling a military force to invade Washington, D.C. and depose the "tyrannical" Lincoln administration. A congressman who stands in Liberty's way is murdered, prompting a government investigation.
The investigator is John Benedict Carver, a private detective and veteran of the Mexican War. He is recruited by an old friend to work for a secret organization within the War Department to infiltrate Confederate espionage. Carver is despondent following the recent deaths of his wife and daughter, and he accepts the assignment as a way to escape from his grief.
The trail takes Carver to Baltimore, where he meets a boardinghouse widow named Lucille Winters. As widows they share their pain and grow affectionate. Meanwhile, Carver learns that there is more to the Liberty investigation than just a simple murder. What begins as a routine investigation becomes a race against time as Carver must uncover the sinister plot and expose Liberty before he launches his troops on the defenseless U.S. capital.
This report prepared by Walter Coffey