'Sherlock' season 4 air date, spoilers news 2016: Mark Gatiss teases glaringly obvious clue missed by fans; Netflix release date bared?

"Thatcher," "Smith," and "Sherrinford" were the three keywords provided to set the tone for "Sherlock" season 4. Fans started theorizing what those three words could mean, but according to series co-creator and star Mark Gatiss, who plays Mycroft Holmes in the show, fans missed a glaringly obvious clue for the upcoming season.

Radio Times caught up with Gatiss during the members' talk at the Victoria and Albert Museum in London and asked what he could dish about the upcoming installment. Gatiss said very obvious clues on "Sherlock" season 4 have been released, clues that fans could think about, but apparently, they missed the target. He was careful, though, not to reveal what the missed clue is.

According to Gatiss, some fans are picking up details that are not connected in any way to the Benedict Cumberbatch-starrer. He then goes on to say that once season 4 starts airing, a plot will be presented that even a casual viewer (meaning someone who's just tuned in to the series) will understand. With that, Gatiss came short of saying that the overly complicated theories fans have been mulling over are all inconsequential to the real storyline.

"There are things that come to fruition in this series which we've been planning for years," the actor said. "But people also find things that aren't there. Which is my favorite. And then miss the blindingly obvious things that are there. People read an awful lot into it."

One theory he dashed had something to do with James Moriarty's (Andrew Scott) death, which some fans linked to a fairy tale by the brothers Grimm. He said, "That's obviously not going to happen because this has to be something for the casual viewer, who's not going to say 'Oh I see...'"

Meanwhile, Netflix Life estimates that "Sherlock" season 4 could start streaming on Netflix by June or July 2017 based on previous releases of the series on the streaming giant. Seasons 1 and 2 of "Sherlock" released in January for TV, with Netflix releasing it by June of the same year. If the pattern holds, then a June or July release date is to be expected.

"Sherlock" season 4 is slated to drop in on BBC on Jan. 1, 2017.