Following his fall from grace in London and a stint in rehab, eccentric Sherlock escapes to Manhattan where his wealthy father forces him to live with his worst nightmare – a sober companion, Dr. Watson. A successful surgeon until she lost a patient and her license three years ago, Watson views her current job as another opportunity to help people, as well as paying a penance. Holmes resumes his work as a police consultant in New York City and Watson has no choice but to accompany her irascible new charge on his jobs. But Sherlock finds her medical background helpful, and Watson realizes she has a knack for playing investigator. With the mischievous Sherlock Holmes now running free in New York solving crimes, it’s simple deduction that he’s going to need someone to keep him grounded, and it’s elementary that it’s a job for Watson. Amidst Sherlock and Joan’s battle with tech billionaire Odin Reichenbach, the investigators receive word of their old enemy and Sherlock’s former love, Jamie Moriarty. Reichenbach inadvertently provides Sherlock and Joan with a lead that could give them evidence that brings him to justice. Sherlock and Joan join forces with Holmes’ father, Morland to enlist his vast criminal network to help disassemble Reichenbach’s crime prevention system. Holmes and Watson receive a shocking request to collaborate from their foe, Odin Reichenbach, when the tech billionaire asks them to test his new crime prevention system. Tasked with investigating someone the program predicts will soon commit a crime, the duo worries Odin will take drastic action before they conclude their inquiry. Holmes and Watson work to determine if a long dormant serial killer has resurfaced in the wake of a sculptor’s murder in New York City. Also, Watson suspects Holmes is keeping something from her regarding tech billionaire Odin Reichenbach.