Isle of Forgotten Sins is one of those rarities I discovered at my local library. In this case, this was one of Edgar G. Ulmer's low-budget poverty row pictures he made for PRC. John Carradine and Frank Fenton are rivals for gambling club owner Gale Sondergaard but they put aside their differences for a chance to get sunken treasure. Ms. Sondergarrd and her girls (which includes a crafty Veda Ann Borg) come along but all of them seem to be pawns for Sidney "Charlie Chan" Toler and his partner Rick Vallin. Also briefly appearing is Bill Edmonds-Mr. Martini in It's a Wonderful Life-as the island chief. Enjoyably and breezily fast-paced (whenever possible) B-movie that benefits from Ulmer's expert direction and a suitable underscore by Leo Erdody (who like me was born in Chicago, Ill.) mixed in with some public domain classical music. The composer is billed by his last name here. If there's some quibble, it's how some scenes obviously reveal how some boat scenes use a toy model and the underwater ones reveal the diving suit, which is also a small plaything, being manipulated. Otherwise, great fun with even some singing from one of the girls not marring the storyline too much.