Sherlock Holmes (Jonny Lee Miller) is a recovering addict who meets Joan Watson (Lucy Lui) as his 'sober companion'. Initially their relationship is strictly professional, and somewhat frosty, but they grow to understand and work with one another, eventually forming a friendship and partnership. Together they assist Captain Gregson and Detective Bell of the NYPD, where Holmes' observational abilities and deductive talent unravel a series of complicated cases. Alongside his police work, Sherlock struggles with a past he left behind in London involving an ex-girlfriend Irene Adler, a 'nemesis' in Moriarty, and an absent father.