Upon their return, Russell and Holmes embark on a charade of estrangement from each other, hoping that Holmes's vulnerability will draw their enemy in for the kill. However, playing the part takes a toll on both. They are also under heavy surveillance by the enemy and unable to converse frankly. In May, Russell discovers that the slashes on the cab seat spell MORIARTY in Roman numerals according to Base 8, and connects the case with her missing maths tutor, Patricia Donleavy, who had given her exercises in Base 8. At her lodgings, she finds Holmes, who informs her that their attacker is preparing to strike. The two make for Sussex to set a trap, only to find Donleavy already lying in wait for them. Donleavy reveals herself as the orchestrator of Jessica Simpson's kidnapping and the revenge-seeking daughter of Professor Moriarty, whom Holmes hurled to his death at the Reichenbach Falls. Holmes provokes her to attack him, and Russell intervenes, leading to a struggle in which Donleavy is killed and Russell is heavily injured by the same bullet.