Kindly and brilliant inventor David Mallory (a fine and sympathetic portrayal by Boris Karloff) invents a new security system. Mallory gets abducted by a gang of nefarious burglars who force the old guy to assist them with a series of robberies. Directed with real flair by Lloyd Corrigan, with a nonstop brisk pace, colorful characters, crisp black and white cinematography by George Robinson (the artful use of fades and dissolves is especially impressive), a nice sense of playful humor, snappy dialogue, a tight and engrossing script by Jack Moffitt, a lighthearted tone, a robust score, and a lively and exciting climax, this movie overall sizes up as a highly entertaining item. Moreover, it's a total treat to see Karloff portray a rare decent and amiable good guy part: With his failing eyesight and gentle manner, David Mallory makes for a very appealing protagonist. The fetching Jean Rogers adds charm and spark as Mallory's perky daughter Joan, Alan Baxter does well as ruthless gang leader John Baron, Hobart Cavanaugh almost steals the whole show with his amusing turn as wormy low-life small-time crook Petty Louie, and Ward Bond is suitably menacing as hulking strong-arm thug Fingers. A fun flick.