Before "Doctor Who" returns with season 10 on BBC and BBC America next year, here is a roundup of what's already known about the upcoming installment of the science-fiction series.

The latest development on the show is the return of a previous character. Missy is back, actress Michelle Gomez confirmed at the recent MegaCon in Orlando, according to Doctor Who News. Missy, the newest form of Doctor's ultimate foe, The Master, was introduced in "Deep Breath."

She was last seen in the previous season's "The Witch's Familiar." She is known to be more cunning and a trickster than the previous forms of the Master. It can be remembered that her last scene was when she thought a very clever idea. Some say this season will be the time she will unveil this great idea.

Meanwhile, season 10 will be the last chapter for showrunner Steven Moffat. Before stepping down from his role, he revealed that it was Lenny Henry's advocacy for screen diversity who inspired him to cast a non-white companion for the doctor.

"I'd been listening to what Lenny had been saying," showrunner Moffat told Doctor Who Magazine (print version). "We decided that the new companion was going to be non-white and that was an absolute decision because we need to do better on that. Young people watching the show have to know they have a place in the future."

Moffat added that it would even be "amazing" to have two non-white leads on "Doctor Who," meaning both the doctor and the companion would be non-white. He said that "it should happen one day."

Lead star Peter Capaldi, meanwhile, has revealed on Cultbox about what to expect from his character Dr. Who next season. He described the doctor to have more interesting combinations because of all of the things that he has gone through. He added, "In some ways he's much more amenable, but in other ways he's even darker."

"Doctor Who" season 10 will premiere sometime in 2017.