Aristocrat Charles Lenox is not only a born amateur detective, but also a true gentleman, always ready to perform a noble deed. Therefore, when Lady Annabel Payson asks him for help - her son George disappeared without a trace straight from Lincoln College in Oxford, he immediately goes there. What happened?! There is a lot of evidence in the missing person’s room, including a cat stabbed with a dagger, an encrypted note and a card of a certain society “September”. But what is the connection between these evidence? Lenox soon learns that the September Society includes officers who served in India. And here is a mysterious coincidence: George Payson’s father died in India, and under extremely mysterious circumstances. But Charles Lenox does not believe in the coincidence of such coincidences!..