Forty-year-old Professor Kauffmann is awakened by the loud, insistent trilling of the electric bell. He slides his hand, holding a weapon, into his gown's pocket and goes downstairs to open the door. To his relief, it is Elphinstone who is ringing the doorbell in the middle of the night. The young man enters Kauffmann's house without being invite, saying that he is in a great danger, and that so is the professor as well. What do Professor Kauffmann and Elphinstone have in common? What is the danger that is lurking over them? How will they handle the situation? mFind all the answers in Rafael Sabatini's 1918 novel "Intelligence".