The Beekeeper's Apprentice By Laurie R.

The Beekeeper's Apprentice is a mystery novel written by Laurie R. King about Mary Russell, an orphaned fifteen-year-old who lives with her aunt in Sussex Downs. One day in April 1915, with her nose in a book, Russell almost walked on Sherlock Holmes, fifty-four and retired from his job in London, instead caring for his beehives and elaborate science projects. They quickly bond, and Russell assumes the position of Sherlock's student, and Sherlock the teacher. Mary Russell had a steadfast opinion of Holmes as too soft and undeserving of Holmes's companionship, but when she finally met the man himself, she found that he was kind and oddly likeable, and eventually nicknames him Uncle John. When Russell goes off to Oxford in 1917, she's well-versed in the detective skills of Sherlock Holmes.
At Oxford, Mary Russell studies psychology and a variety of other subjects, including math with her tutor, Patricia Donleavy.
Between terms, Mary Russell solved two quick cases with Sherlock before returning to her studies at Oxford. It was uneventful, until one afternoon in December, when Sherlock showed up at her dormitory severely damaged by a bomb and informed her that there was a bomb at her door that he defused before she arrived. Concerned, Mary Russell took him to his brother Mycroft's house nearby, where they patched up Sherlock up. When they phoned Watson to tell him that they were perfectly safe, he assumed where they were and set on his way to Mycroft's. Hours after his departure, Watson's house was blown up by what seemed to be a suicide bomber. Soon, another bomb went off at a hotel that Holmes had used as a hiding place while he was still working in London, and had very obvious clues, such as slashes on a cab seat she used to get there that were obviously Roman numerals. Sherlock and Mary Russell deduced that the bomb was set off by a woman, and a rich one at
that.
Russell and Sherlock made plans to ' vacation' in Jerusalem and Palestine, to throw their pursuer off their trail.
Over the trip to Jerusalem and Palestine, Sherlock and Russell enjoy themselves, even in their grimy conditions. Sherlock learns more about Russell's namesake, and she tells him her Dream-- a nightmare that repeats over and over and over. She dreams about leading her family to all plunge off a cliff, with Mary just barely surviving and her parents and brother dying tragically. When they board the ship to return home, they devise a plan; to return acting as though they had a falling out, that they had fought and that they wouldn't return to each other. Sherlock successfully made himself look like a broken man, with no preference between his life or death and as if an illness had befallen him. Mary Russell returns to Oxford, and her talents become precise, cold and beautiful like a diamond. She observes people stalking her, but pretends not to notice. Eventually, she decodes the roman numerals, revealing the word MORIARTY in a deep code. Mary Russell recognizes the code and word from her studies with Mrs. Donleavy, who was 'sick' at the time.