There is one line in last week’s ‘The Lying Detective’ that really jumped out at many fans. When Sherlock outsmarts Culverton Smith by concealing a fourth recording device in his hospital room, he says: “Must be something comforting about the number three. People always give up after three…”

While nearly everyone believes it will be of importance down the line, fans are split on what it could be hinting at. We, like several others, suggested it could be suggesting that there is a fourth Holmes sibling to be revealed in ‘The Final Problem.’ Others, however, think it could be hinting at a secret fourth episode of Series Four. Most likely in the form of a special to be aired later this year.

At first such a thing sounds far-fetched, but the cast and crew have been very open about the fact that it is getting harder to regroup for each season. Why wouldn’t they sneak in an extra episode while they were already together?

At the BFI screening for Sunday’s finale, co-creator Steven Moffat was asked about the rumour. And he swiftly denied it. Here’s how responded:

“It doesn’t reflect the fact that there’s gong to be a fourth episode – for heaven’s sake, what kind of secrets do you think we’re keeping?! Let’s go home and check. Oh look episode four… the lost special…”

Well, there you are then, nothing to see here… Except. Hang on a minute. Did Moffat intentionally reference a Conan Doyle detective story called ‘The Lost Special’ when he said that? Wouldn’t it be a very Mofftiss thing to do to reinterpret a piece of the Sherlock Holmes creator’s work in an unexpected way? As every Sherlock fan knows, Steven Moffat is not averse to lying to keep Sherlock‘s secrets hidden.

Or, alternatively, it’s all a coincidence! We’ll have to wait and see…

Sherlock: ‘The Final Problem’ airs this Sunday at 9PM on BBC One and at 7PM on PBS Masterpiece.

Radio Times