"Warner Oland vs. Boris Karloff" read the billing on the opening credits of Charlie Chan at the Opera. Karloff plays a once-famous opera star who has long been confined to an insane asylum. He escapes, ostensibly to seek revenge on the diva wife (Nedda Harrigan) who'd betrayed him years earlier. Karloff shows up during the performance of a new opera, and within minutes the murders start. Detective William Demarest figures the case is open and shut, but oriental sleuth Charlie Chan (Oland) is not thoroughly convinced of Karloff's guilt--nor is he certain that Boris is genuinely insane. To give away the ending would be churlish, but we can note that Charlotte Henry plays Karloff's daughter, who has been raised to believe that her father was dead. Considered by some Charlie Chan fans to be the best of the Warner Oland efforts, Charlie Chan at the Opera is distinguished by excellent production values, and by an original opera composed by Oscar Levant--who allegedly agreed to this assignment provided he could include the word "Silencio!" in his lyrics.