It is present day London.

A Metropolitan police officer, Sherwood Lachlan Holmes, average in every way, has been involved in a bomb blast while on duty. He wakes some months later in a psychiatric hospital, but he is not the same. His IQ spiked to genius levels, his speech is distinctly Victorian and vocabulary has impressively expanded.  Attending psychiatrist, Dr Jill Watson, notices through her examinations that his deductive powers of observation are unique and exemplary.

When a number of bodies are discovered around London with elaborate clues and notes, Watson is called upon by Chief of Police, George Engle, to explore the mind of an illusive murderer.  Little does she know her ammoying patient, "Lock', will be the key to solving a dangerous game of cat and mouse.