"Enemy to those who make him an enemy, friend to those who have no friends." Boston Blackie is an ex-con who decided to put his knowledge of the underworld to use for good. Now a detective, he still has a way of getting mixed up with plenty of murders, missing jewels and misunderstandings. As a former criminal, Blackie has no love for the police or for the ineffectual Inspector Faraday who always got in his way. The humorless Farraday was on the receiving end of Blackie's bad puns and word play. Luckily, Blackie could always count on girlfriend Mary Wesley to be at his side - giving him support and spotting clues!