Sherlock, Lupine and I 2.- Last act in the opera

A mysterious murder shakes up the opera world. Irene, Sherlock and Lupine arrange to meet in London. However, Lupin's friends wait in vain, because his father, Théophraste, has been arrested on charges of theft and murder. He is suspected of having killed Alfredo Santini, the secretary of the great composer Giuseppe Barzini. The three children want to clear him of the charges, so they start investigating. Turn after turn - among other things, they save the life of the famous soprano singer Ophelia Merridew in the dirty Bethnal Green district - and finally Sherlock and his companions uncover the culprit whom no one would have ever suspected.