Legendary detective Charlie Chan (Warner Oland) investigates murder most foul at an opera house haunted by a madman (Boris Karloff)... who's giving a performance that's to die for! Terror waits in the wings! For seven years, opera star Gravelle (Karloff) has been locked in an insane asylum, his identity a mystery - even to himself. But when his memory unexpectedly returns, he begins to recall that his wife and her lover tried to murder him - and now he's determined to make them face the music!