BBC's flagship sci-fi series "Doctor Who" will be coming back next year for its 10th season with a set of new characters, including new allies and enemies, as well as a surprisingly dramatic story line.

"Doctor Who" tells the story of a Time Lord called The Doctor who travels through time and space. The Doctor makes it his mission to save various planets in different time period by gathering assorted people called his companions that could help him with his galactic tasks.

The long-running BBC TV show is said to have a less dramatic story line, but will have a lot of action-pack space exploration scenes, as said by "Doctor Who" actor Peter Capaldi.

"I think it's a very action-packed season," Capaldi said, adding that the show's plot has a great potential. He also expressed that the 10th season of "Doctor Who" will have a surprising dramatic twist.

"Doctor Who" season 10 will also welcome a new face to the cast after Jenna Coleman has left the show.

A new character called Bill will be played by Pearl Mackie. Bill is The Doctor's newest companion, and she will provide the story with a fresh take on the concept of time travel.

"It's mad, it's really exciting. There's loads of fans!," 29-year old actress Mackie said in an interview during her first day of filming at Cathays Park in Cardiff Wales.

Furthermore, another new character that will surprise fans in the 10th season of "Doctor Who" is The Doctor's evil self, who is known as The Valeyard. In "Doctor Who" season 10, the characters will soon discover that The Valeyard is an evil reincarnation of The Doctor himself.

As of now, there is still no news as to what The Valeyard's true motives are, but speculations suggest that The Doctor's  evil doppelganger will certainly bring about a series of undesirable events.

BBC's "Doctor Who" Season 10 will air in spring 2017.