Sherlock season 4, episode 2 plunges the series into darkness with its adaptation of “The Adventure of the Dying Detective.”

“Well Watson, we seem to have fallen upon evil days.” Sir Arthur Conan Doyle writes these words in the first pages of “The Adventure of the Dying Detective.” The 100-year-old words weigh heavy on Sherlock season 4, episode 2.

The Case

A mysterious ivory box arrives at 221B Baker St. for Holmes. The box, with a spring-loaded pin, is set to prick Holmes’ finger and inject him with a coolie disease from Sumatra. The detective reveals symptoms of fatigue, high fever, and delirium for three days.

On the third day, Mrs. Hudson summons Watson to the dying detective’s bedside. Between gasps for air and coughing fits, Holmes reveals the circumstances surrounding his illness. Watson tries to help Sherlock, but the dying man refuses any assistance, save one errand.

Watson is to fetch Mr. Culverton Smith, a planter, who is familiar with the disease. The man may resist coming to Holmes’ bedside seeing as Holmes once assisted on a case in which Smith’s nephew died. Tension between the two still lingers.

Watson follows Holmes’ instructions and returns with Smith just moments behind.

The Solution

Sherlock instructs Watson to hide in the small room behind the bedroom and not move no matter what he hears. Smith arrives and reveals that he is responsible not only for Sherlock’s ailments, but also the death of his nephew.

Holmes reveals the entire illness was a ruse. For three days he did not eat or drink to make himself appear haggard and ill.

The Adaptation

“Through the half-open door I heard a high, petulant, penetrating voice,” says Watson of Culverton Smith. For such a short story, the impression of this villain lingers long after its conclusion. The man is described as a incredibly wealthy, busy man who collects the world’s most exotic poisons and keeps them in jars like prizes.

Seems like the type of person who wants to collect the dangerous mind of Sherlock Holmes for his trophy case. But Sherlock‘s Culverton Smith is not going away as easily as he does in Doyle’s origin story.

First seen in episode 1, in a bus ad, the looming presence of Smith looking over Watson’s extramarital troubles hints that Watson is the prey. That is not to say that Holmes does not succumb to a fake (or perhaps true) illness.

But it does suggest that the poisonous ivory box in this case is E.

“The Adventure of the Dying Detective” reveals the long game between Smith and Holmes. Culverton Smith is a patient man, willing to wait days for the news of Holmes’ demise. Choosing to use Watson as a pawn lengthens the game for him to watch from afar. Mary’s death could complicate or assist his devious plan for Sherlock.

However, one major difference exists in the Sherlock season 4 adaptation — Watson is not speaking to Holmes. The canon tale reminds readers how dismissive Sherlock often is of Watson’s talents. Sherlock does the same in the season 4 premiere. Even Watson gets in on the running gag, replacing himself with a balloon at one point.

But the troubles in the present are not founded in a lack of appreciation. Mary’s death, John’s guilt, Sherlock’s guilt, all roll into one massive standoff. At the close of episode 1, Sherlock attempts to bridge the gap between them, but it is John who puts up the wall.

This isn’t a game

Canon Watson runs to Sherlock’s side to share in his friend’s final moments. But Sherlock season 4, episode 2, may not see the blind trust of “The Adventure of the Dying Detective,” return now or ever again.

And, by the looks of the trailers for this season, John and Sherlock may need it as they find themselves in a maze even worse than Moriarty’s game.

Sherlock season 4, episode 2, “The Lying Detective,” airs tonight at 9:00 p.m. on BBC One in the U.K. and 9:00 p.m. on PBS in the U.S.