In the episode, the first to be shot outside New York, Holmes, played by Jonny Lee Miller, journeys back to his former home to look at an old case and, in the process, runs up against his past.

Sherlock Holmes will be taking a trip when Elementary returns in the fall.
The CBS drama is heading to London, the home of the original Holmes, to film the second-season premiere.
In the episode, the first to be shot outside New York, Holmes, the brilliant, eccentric detective played by Jonny Lee Miller, journeys back to his former home to look at an old case and, in the process, runs up against his past. Watson (Lucy Liu), the companion who keeps him grounded, learns more about Holmes before he moved to New York.
"We couldn't be more excited to have this opportunity to see Sherlock's old stomping grounds and take a closer look at a life that, until now, we've only been able to glimpse through the lens of his recovery," executive producer Robert Doherty said in a statement accompanying the filming announcement. "By meeting old friends and revisiting prior cases, Watson will gain even more insight into Holmes. She'll have to keep up with a Sherlock who is both more comfortable in his surroundings and even bolder in testing the limits of those around him."
The first-year drama (tonight, 10 ET/PT) is averaging 12.9 million viewers and, for the season, is winning its Thursday time slot in viewers and young adults.
The series also is popular internationally, performing well in the United Kingdom, Canada, Australia, Spain, Germany and Italy.