"Charlie Chan at the Opera" was released in 1936 as another episode in the Charlie Chan series. In this version Charlie Chan (Warner Oland) has to sort through clues to determine if an escaped mental patient, Gravelle (Boris Karloff), is guilty of murdering his wife. Gravelle who suffers from amnesia has been confined to a mental institution for years after his wife, Lilli (Margaret Irving), attempted to murder him. He escapes from the institution and tracks her down at a local opera. He manages to replace his wife's lover, Enrico Borelli (Gregory Gaye), in the opera with the help of the Enrico's wife. After the performance, Enrico and Lilli are found stabbed in their dressing rooms.