The Sherlock season 3 finale titled "His Last Vow" will be airing January 12, 2014.

The third and finale episode of the hugely popular mystery drama series will air at 8.30 p.m. on BBC One in the UK. Viewers will be able to watch the episode online via live stream on BBC.

Sherlock's finale episode is set to be explosive as it will feature the detective facing his biggest nemesis Charles Augustus Magnussen, who is set on destroying his life.

The official synopsis is as follows: "A case of stolen letters leads Sherlock Holmes into a long conflict with Charles Augustus Magnussen, the Napoleon of blackmail, and the one man he truly hates. But how do you tackle a foe who knows the personal weakness of every person of importance in the Western world?"

The first episode titled "The Empty Hearse", aired January 1 and became the most watched program on January 1, with nearly 10 million viewers tuning in at its peak. The episode finally showed what happened to Sherlock after he faked his own death in the season 2 finale.

The second episode "The Sign of Three" saw Sherlock facing his biggest challenge as he struggled to give the best man's speech at John Watson's wedding to Mary Morstan.

See the preview trailer below for "His Last Vow," which will air January 12, 2014.

Viewers in the UK would be the first to see the broadcast of Sherlock season 3 on BBC One. Viewers in the U.S. will finally be able to see the season 3 premiere on PBS on January 14, 2014.

Click here for viewing information in the U.S. on PBS.

Sherlock is a British television crime drama with a contemporary update to Sir Arthur Conan Doyle's Sherlock Holmes detective stories. The show was created by Steven Moffat and Mark Gatiss, and stars Benedict Cumberbatch as Sherlock Holmes and Martin Freeman as Doctor John Watson. Six episodes have been produced so far. The first three episodes aired in 2010, and series 2 aired in 2012. Production for series 3 started in March 2013.