New ‘Sherlock’ season puts the sleuth, Watson to the test

The game is afoot yet again in the fourth season of “Sherlock,” but so is complete catastrophe.

The clever and adventurous series takes a definite turn for the worse — for all of its major characters — in the next three-episode round of the PBS “Masterpiece” series (premiering at 8 p.m. Sunday on WTTW-Channel 11).

“It doesn’t lose the humor, but it still goes to places that I think are darker than we’ve gone to before, for all of us,” says Martin Freeman, who stars as devoted assistant John Watson to Benedict Cumberbatch’s British detective Sherlock Holmes.

As Sunday’s premiere begins, Sherlock’s “got his mojo back,” says co-creator Mark Gatiss. He’s coming out of a drug-induced stupor to figure out how arch-villain Jim Moriarty (Andrew Scott) is cyber-taunting him from the grave, and now Sherlock is “high on life.”

He happily takes a new workload of cases with John and his wife Mary (Amanda Abbington), who’ve just had a baby. But a rash of thefts involving a bust of Margaret Thatcher brings Mary’s sinister past as an assassin to the fore, leading to deadly ramifications.

“It’s always exciting to play stuff that is thrilling and dangerous and dramatic and funny, and I think that’s what Mary is,” says Abbington.

The harrowing climax in Sunday’s premiere leads to massive emotional fallout that threatens to create a permanent divide between Sherlock and John. “Their friendship is tested to the ultimate,” Abbington says. “If they can survive this, then they will actually survive anything.”

The situation is particularly trying for Sherlock, who’s evolved over the course of the series from eccentric recluse to having friends and even getting along with his brother Mycroft (Gatiss).

“He’s never going to be like the rest of us. It’s just he has developed. He has learned to a greater or lesser extent how to do human,” Gatiss says. “It was always Mycroft and his upbringing that taught him to eliminate emotion from his life. He’s becoming bonded with people and is slightly devastated by the consequences.”

Watson is also in for a change, from the show’s “stable, reliable, solid rock” to a man dealing with temptation and guilt, Freeman says. “It’s good to have that moral compass go off pole a little bit.”

Toby Jones guest stars as bad guy Culverton Smith in the second episode, titled “The Lying Detective” that’s based on the Sir Arthur Conan Doyle story “The Dying Detective.” Freeman says Smith rivals Moriarty as the worst person Sherlock’s encountered.

“It’s generally the darkest episode we’ve done, and Toby is very, very scary,” Gatiss says.

The season finale “really does hit you behind the eyes,” says Abbington. “The Final Problem” marks the first time the show has used a canonical Doyle title — the original 1893 story, in which the author first killed the genius detective.

“It’s a great title and it has the requisite air of doom,” Gatiss teases.

So should fans wonder about Sherlock’s fate?

“Everyone should worry, shouldn’t they?” Gatiss says with a laugh. “I think we should all be worried.”

Brian Truitt, USA TODAY