"Sherlock" will be back with its new season, "series 4" in 2016, but before that, BBC will be airing a "special" episode in time for Christmas 2015. Given the fan-craze for the crime drama based on Sir Arthur Conan Doyle's Sherlock Holmes detective stories, every brain teaser, rumour and spoiler has been dissected and thoroughly researched, much ahead of the "Sherlock: Series 4" premiere in 2016.

As of now, the spoilers we have for season 4 of "Sherlock" is that in three upcoming episodes, Sherlock (Benedict Cumberbatch) and John Watson (Martin Freeman) will be taken into deeper and darker water than ever before. With a mission to outmatch series 3, both Sherlock's nemesis Jim Moriarty (Andrew Scott) has to be killed. 

It has to be acknowledged that the feud between Moriarty and Sherlock is one of intellect. While it is not known if the villain is truly alive or simply messing around with all of England in an after-life video shown in series 3 finale, it is certain that if the two masterminds come face-to-face in the series coming out in 2016, it will make for a great episode(s).

Meanwhile, the death of Charles Augustus Magnussen (Lars Mikkelsen) – the only person Sherlock truly hates – is almost certain and Mary Watson (Amanda Abbington), who was threatened by the "terrifying" villain in season 3, will give birth to her and Watson's baby. In "His Last Vow", Sherlock had said: 'I've dealt with murderers, psychopaths, terrorists, serial killers. None of them can turn my stomach like Charles Augustus Magnussen". 

While there are rumours that Molly (Louise Brealey) and Sherlock may finally hook up, Cumberbatch, during an interview with Nerdist, had outed his character as gay. In reply to a comparison between Sherlock and Dr Who he said: "Sherlock talks fast and is clever, that's literally the only bracket they share. They've got different dress senses, different tastes in the sex of their partners..."

There are also rumours that suggest his third brother would also make an appearance in "Sherlock Series 4".