Syme and de Worms eat dinner and discuss their upcoming meeting with Dr. Bull. Syme is so relieved to have a companion that he acts giddy. de Worms reminds him of the danger inherent in their visit with Dr. Bull: their goal is to “steal a secret from a very sharp, very strong, and very wicked man” (59).

When the two men reach Dr. Bull’s room, he sits at a table dressed in a white shirt and black breeches. The professor tries carefully to extract the details of the assassination plan without arousing Dr. Bull’s suspicion, but Dr. Bull listens silently. Syme grows suspicious, and though the professor discourages him, he leans across the table and asks the doctor to take off his glasses. Dr. Bull hesitates and then removes his glasses. When Syme sees the doctor’s face, he throws his blue card on the table, proclaiming he knew Dr. Bull was a detective, adding, “I knew my intuition was as infallible as the Pope” (65). The professor throws down his card, too. Dr. Bull laughs and puts his card on the table with the other two.

Dr. Bull explains that he sent the Marquis to Paris to assassinate the Czar and the French president with a bomb.