Night in Naples. An explosion shatters the silence, and an engineer from Erlangen is blown up along with his car. Distrusting the local authorities due to their connections to the Camorra and concerned for the life of the young widow in the area, the Erlangen police send Commissioner Mütze undercover to Italy. For cover, Mütze has brought along his friend Karl-Dieter, who is excited to finally experience the city of Caruso, as he is a big fan of the opera legend. The two of them try in vain to persuade the widow to return to Germany. What had she and her husband wanted in Naples? Was the engineer's past with the BND catching up with him? The clues lead back to Erlangen... A wonderful crime comedy about Southern Italian lifestyle, a street dog to fall in love with, and the greatest singer of all time.