When international politics cause a group of Russian basses to arrive in Allemonde just in time for the annual opera festival, the singers' intense competition quickly gets out of hand. But after one of the Russians disappears and another is killed in a bizarre accident, Chief Inspector D.T. Giovanni concludes that at least one murderer is terrorizing the duchy and must be caught. Meanwhile, his relationship with Annalisa Canali is becoming strained when she wonders why the chief inspector won't make their new status public. The whole messy business has become, quite clearly, a mystery on an operatic scale!