On New Year’s Day the BBC and PBS finally got their sh*t together and aired Sherlock at the same time, instead of making the US wait weeks for it, which is dumb and pointless in this day and age. It’s the one-off, Victorian-set holiday special—even though it really doesn’t have anything to do with the holidays—titled “The Abominable Bride”, and it’s meant to hold us over until series four airs sometime in twenty-whenever Benedict Cumberbatch has the time. Sherlock is at its pop cultural zenith, so “The Abominable Bride” is less about attracting new viewers and more about keeping the show relevant during the long hiatus between series. It’s a sort of indulgence, which is actually the special’s chief problem—it’s indulgent.

All the familiar characters are here, anchored by Cumberbatch as Sherlock Holmes and Martin Freeman as Dr. Watson. The episode—which is really a TV movie—is written by series co-creators Steven Moffat and Mark Gatiss, and it’s directed by Douglas Mackinnon, who has directed several of Moffat’s Dr. Who episodes. It’s set in Sir Arthur Conan Doyle’s native Victorian era, and for its first half, “The Abominable Bride” is a neat trip down the could-have-been rabbit hole. Mackinnon deftly combines classic Holmesian iconography like the deerstalker hat, Holmes’s pipe, sooty gas lamps, and particularly the Reichenbach Falls, the waterfall where, in Doyle’s telling, Holmes and Moriarty meet their mutual doom. Of course in the updated version, it was a hospital roof, but “The Abominable Bride” is very invested in the Holmes/Moriarty conflict.

Which is where things start to go wrong. There is endless joy in watching Andrew Scott play Moriarty—he’s every bit as indelible in the role as Cumberbatch is as Sherlock—and Moffat and Gatiss keep finding ways to bring Scott back (finding Moriarty chained up in the recesses of Sherlock’s “memory palace” in series three was a nice touch). But they overplay their hand here, getting cute with the possibility that Moriarty somehow survived blowing his brains out on the roof of St. Bart’s Hospital. It even has to tie into the mystery of the bride, a ghostly figure charged with multiple murders who also seems to have survived a self-inflicted head wound.

This is fan service, plain and simple. Scott is popular as Moriarty and people want to see more of him, even though the character is dead, so he’s shoehorned into the episode even if it’s really not working for the story. “The Abominable Bride” actually starts out as a solid ghost story and a good mystery, but the more it becomes about whether or not Moriarty survived in the present, the less interesting it becomes. Moriarty so takes over the episode that the resolution to the mystery of the bride feels rushed and not particularly well planned. Part of what makes Sherlock so good is that at heart it’s just good mystery stories, but this is one of the weakest mysteries they’ve done. It’s just not a satisfying reveal.

But it’s not a total loss, either. The mystery doesn’t hold up, but we do get some actual character development from Sherlock. Cumberbatch is a screen tyrant paired with a domineering character, so his Sherlock is a towering figure. He’s so smart, so clever, and so capable that he’s virtually invincible—he even cheated death! But that doesn’t leave Cumberbatch anywhere to take the character over time, and it’s imperative that Sherlock have some actual development. So series three unwinds Sherlock’s control, and he falls back into his drug habit, which is where we find him in this special—fully relapsed and backsliding into self-destruction. The Sherlock going into series four is one with a hair trigger on his self-control, who may not be operating at his peak.

In a way, “The Abominable Bride” is a ninety-minute trailer for Sherlock series four. The mystery of the bride would have been better served had the special been as advertised—a one-off alternate take set in the Victorian era that has nothing to do with the modern storyline. But instead it’s a patched-together combination of Victorian retelling and modern continuation, and the result is that it’s messy and badly paced.

But fans of the show will be happy because Molly Hooper stands up to Sherlock and everyone sh*ts on Anderson and Moriarty sucks on a gun in a suggestive manner, and there’s plenty of fanfic-baiting exchanges between Sherlock and Watson. Fan service was the source of series three’s problems and it’s a problem here again. I just hope Moffat and Gatiss—and I suspect it’s more Moffat than Gatiss—don’t worry so much about appeasing Tumblr’s appetite for homoerotic subtext in series four. I miss Sherlock’s puzzle box mysteries.