Although Treasury Department detectives wouldn't seem to live a life of danger, Ford does in this picture as he tries to prove an underworld crime boss, known only as the "Big Fellow," guilty of tax evasion. The hood owes $3 million in back taxes, so Ford and partner Whitmore head to Chicago to crack the case. They begin asking a lot of questions--too many for the Big Fellow and his corrupt Italian "family." When T-men try to get some answers from the mob's bookkeeper, he is silenced with a gunshot. One by one the contacts are bumped off. When Ford's wife's safety is placed in jeopardy, Ford seriously debates giving up the Treasury Department for a quiet life with his family. He is put back on track, however, by a stirring patriotic speech delivered by the old Italian mother of one of the dead contacts. The dead man's daughter then supplies Ford with the necessary figures and records, which give him solid evidence. With assistance from the Big Fellow's disloyal lawyer, Ford and the feds topple the Big Fellow. Clearly inspired by the methods the government used to convict Al Capone of tax evasion, THE UNDERCOVER MAN is based on an article written by Frank J. Wilson, who reportedly was the man behind the bust of Capone.