The title states the case in Monogram's Don't Gamble with Strangers. It's all about a pair of crooked gamblers, Mike (Kane Richmond) and Fay (Bernardine Hayes), who pose as brother and sister to lure in suckers. After several months of penny-ante activities, Mike and Fay take over a posh gambling joint. Their downfall is assured when Fay begins exhibiting unsiblinglike jealousy over Mike's attentions to gorgeous Ruth Hamilton (Gloria Warren). Mike is shot full of holes; the police believe that Ruth did it, while the audience thinks that Fay did it, but a ballistics tests proves everyone wrong. An unexpected denouement reveals that crime does pay once in a while.