'Sherlock' season 4 release date, spoilers news: New season will be 'darkest' yet; 'Sherlock' team teases three names from season 4

The cast and crew of "Sherlock" descended on Comic-Con this weekend, where they unveiled the trailer for "Sherlock" season 4.

Following the popular crime drama's long hiatus, it sounds like the "Sherlock" team is giving fans a real treat with the upcoming season. During the panel, the show's cast and crew said that the long-awaited fourth season will be the "darkest" yet.

"It's really dark," "Sherlock" actress Amanda Abbington said. "It's the darkest that Steven [Moffat] and Mark [Gatiss] have written."

"When we read them, all of us, we were kind of overwhelmed by them because they were shocking and amazing as always," she added.

Series star Benedict Cumberbatch also hinted at some tearful moments in the show's new season and said: "It's a genuine emotional roller coaster. The learning curves, they're massive."

"Sherlock" cast members Abbington and Cumberbatch were joined by creators and executive producers Moffat and Gatiss as well as producer Sue Vertue at the show's Comic-Con panel on Sunday, July 24.

"Sherlock" season 4 will be the show's first new season in three long years.

When asked about the show's future beyond season 4, the "Sherlock" team was remarkably tight-lipped.

"We have no idea whether it will be the last one or not," Moffat told the crowd.

"We always hope to carry on," Gatiss added. "Everyone loves the show."

When asked specifically if there will be a season 5, Moffat teased, "Why is everybody assuming they survive season four?" "We told you it was dark," he added with a laugh.

Despite the absence of major spoilers during the Comic-Con panel, the "Sherlock" group did manage to drop three key names from season 4. These were: "Thatcher," "Smith," and "Sherrinford."

Fans will have to wait until "Sherlock" returns with season 4 to find out who these are and what roles they play in the "Sherlock" universe.

"Sherlock" season 4 will consist of three 90-minute episodes and will debut on PBS' Masterpiece in 2017.