'Sherlock' Season 4 won't be coming back until late 2015, but although the final release date has yet to be finalized, executive producer Steven Moffat said that fans can expect "darker and devastating" surprises that will topple the last season.

"It's going to be full of surprises for you, and for us and for everybody. I think we just know to expect the unexpected now," Moffat said, "We practically reduced our cast to tears by telling them the plan."

Honestly, Mark [Gatiss] and myself are so excited with what we've got coming up, probably more excited than we've ever been about Sherlock," he added.

Gatiss, on the other hand, told Entertainment Weekly that the current 'Sherlock' storyline is a challenging feat to work on, "We always start with a re-introduction that builds toward a darker climax - we might just be going darker. We've got a very, very good set of ideas," he added.

BBC's crime drama series encountered issues of delayed production due to casts and crews' conflicting schedule with other movie and television projects. However, Moffat assured fans that despite time constraints, he is confident that the team will "keep coming back" to shoot 'Sherlock'.

Meanwhile, the show, starring Benedict Cumberbatch and Martin Freeman as lead actors, bagged a total of seven nominations for the 66^th Primetime Emmy Awards and won four awards including Lead Actor in a Miniseries or Movie and Supporting Actor in a Miniseries or Movie. Unfortunately, both Cumberbatch and Freeman were not present at the event last August 25 to claim their recognitions.

"We've won outside of America and we thought that phase was dying down," Moffat said, "As shows get older, they don't win as often. We're delighted that we've made it here and hopefully this will get more people watching the show."