Benedict Cumberbatch and Martin Freeman returned as Sherlock Holmes and John Watson for a one-shot stand-alone episode that through the miracle of flashbacks was mostly set in the 1890s. (PBS will air the special again on Jan. 10, 10 p.m., ET, check local listings.)

The setting wasn’t the problem. The problem was that while Sherlock has always thrived on self-referential dialogue, packing scripts with clever asides we can all enjoy, in this episode the navel-gazing at times overshadowed the storyline.

That didn’t render “The Abominable Bride” unenjoyable. Much of the dialogue remained engaging, and the flashback framework was constructed in a way that gave us a different angle on the Holmes/Watson relationship.

That was fine.

Nor did either Cumberbatch or Freeman disappoint. In a sense, a Victorian-era episode was perfect for Cumberbatch, because the Victorians were fond of the concept that art should seem as effortless as if one had created it while falling off a horse. Cumberbatch has that kind of ease with Holmes, making the difficult look easy.

But the show’s familiar camera tricks, zooming and tumbling from one scene to another, flirted with excess. If we weren’t time-traveling 120 years, we were toggling between what was really happening and what was happening in Sherlock’s mind.

Again, much of the show has always been built on those inner workings. It’s most effective, however, as a seasoning, spicing up an anchor story. “The Abominable Bride,” based on Sir Arthur Conan Doyle’s “Case of the Blue Carbuncle,” too often seemed to let the story drift to the side.

Much of the emphasis on the machinations of Sherlock’s imagination was deliberate, it’s true, since the episode was built in part on Sherlock’s relationship with his alpha nemesis, Jim Moriarty (Andrew Scott). Moriaty died in a previous series, of course, which is what makes his reemergence here so interesting.

But there’s a line between psychological profiling and navel-gazing, and if we’re going to resurrect Moriarty, let’s make him more than a plot device.

All that said, there’s also this: We need to be grateful we’re getting any new Sherlock episodes at all.

Cumberbatch has risen into such demand lately, partly due to his work on Sherlock, that another multi-episode series, at the moment, was out of the question. This one 90-minute special was all the time he had, and we do appreciate it. Better to have this than not to have had it.

Maybe we’re just spoiled, and we probably should watch again when PBS reruns it. But on Friday, Sherlock didn’t feel like it was reaching its past standards.