While CBS' 'Elementary' recently had some exciting news of its own, details of the BBC's 'Sherlock' season 3 continue to leak out as the acclaimed modern-day adaptation goes before cameras. The latest 'Sherlock' news to hit reveals that the second episode of the upcoming series will bear the title "The Sign of Three," but does its significance suggest an appearance from a famed literary character? Get the latest 'Sherlock' spoilers inside!

The BBC's 'Sherlock' may pride itself on the complex mysteries inherent, but not every secret of production can hide from clever fans of the Benedict Cumberbatch/Martin Freeman drama. After learning that 'Sherlock's season 3 premiere "The Empty Hearse" gave reference to Sir Arthur Conan Doyle's return story "The Empty House," we've found that the second chapter of series 3 seems similarly foreshadowing.

"The Sign of Three" will follow "The Empty Hearse" in 'Sherlock's third season, likely referencing Doyle's story "The Sign of Four," in which John Watson was first introduced to future wife Mary Morstan. This would certainly fit with recent set photos, which revealed that Martin's real-life partner Amanda Abbington would take a major role in an upcoming episode.

Mum as ever though, Steven Moffat would only admit to Deadline that Abbington's character has a “significant impact” on both main characters, and could recur in a number of the three episodes each season.

Well, what say you? Do you think "The Sign of Three" will definitively introduce Mary Morstan? What classic stories would you like to see adapted in 'Sherlock's' upcoming seasons?

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