Watson dives into Sherlock's cold case file and finds the rare dinosaur fossil that turned a scientist into a killer.
Sherlock and Watson investigate a mob murder that hits close to home for Detective Bell.
Sherlock uncovers another layer in the mystery that is Moriarty when a young girl is kidnapped.
Sherlock decides to sponsor a fellow addict while Watson reconnects with a former client.
Sherlock clashes with the NYPD while pursuing an elusive serial killer.
Mycroft gives Sherlock some unsettling news while Watson takes the lead on a double-murder.
Mycroft comes to New York with a murder case, an ex-fiancee and some unfinished business with Watson.