Raymond Griffith's famed nonchalance adds to the humor of this delightful mystery-comedy. During a posh party on a houseboat, a valuable diamond necklace is stolen. The host, who also happens to be the district attorney (Edward Martindel), announces the theft and turns out the lights to give the thief an opportunity to return the necklace. When the lights come back on, the district attorney is dead with a knife in his back. The coroner (Griffith) arrives, quite vexed that this assignment is taking him away from a night at the opera. Since business won't wait until after the show, he decides to solve the crime within the next 20 minutes so he can still get there on time. Everybody is a suspect, but Griffith manages to unmask the real killer -- the deputy district attorney (Earle Williams) -- along with winning the heart of the dead man's ward (Dorothy Sebastian), who accompanies him to the opera. The screenplay to this witty feature was written by Jules Furthman, whose impressive writing career would include films such as Blonde Venus, Mutiny on the Bounty, and To Have and Have Not.