Frank Nitti decides to import a large amount of heroin - $2 million worth. Eliot Ness is soon onto him and arrests the delivery man, Mr. Yang from Shanghai, but he no longer has the goods and they have no reason to detain him. Ness and one of his men travel to San Francisco to see if they can determine how the goods were smuggled into the country and determine that it entered on a passenger cruiser and was then shipped by air to Chicago enclosed in a large globe. 

Ness arranges parole for convict Al Remp, in order for Remp to obtain information enough to convict his old boss, bootlegger Fat Augie Strom. Remp's wife is not informed about the fact that Remp is actually working for Ness, and begs Ness to put her husband back in jail where she feels he's safe from the temptation of power. As he works his way up in Strom's organization, will Remp be able to resist the idea of going back to his old way of life?