“Doctor Who” fans get an extra gift on Christmas day: a new episode. The 2015 Christmas special will take fans on a fun adventure with the Doctor (Peter Capaldi) and his wife River Song (Alex Kingston). The Doctor will be trying to avoid the holiday spirit, but he can’t turn away from a crashed spaceship that needs his help. Of course, they’ll find themselves in even more trouble once they make a couple of enemies. Find out what you need to know about the holiday “Who” special:

1. River Doesn’t Recognize Him – River hasn’t met the Twelfth Doctor yet, so she doesn’t realize she is working with her husband. It isn’t clear how long she’ll take to realize her love has a new face.

2. A Cyborg – As seen in the episode poster, the Doctor and River will face a robot. However, it isn’t just a robot. Inside is King Hydroflax (Greg Davies), who is also part human. “King Hydroflax is a very bad King, who as it turns out is mostly cyborg - in fact only his head has remained,” showrunner Steven Moffat told the BBC. “He’s a vicious, terrible and deeply stupid man and a dreadful tyrant.”

3. Fun – After the dark ending of Season 9, the Doctor and his fans could use a laugh. “It’s a wonderful slapstick caper,” Kingston told the BBC. “There’s a lot of great laughs, there’s a lot of fabulous River one-liners. The fans are going to love the things she says and there’s a lot of play.”

4. New Characters – In the spirit of fun, a new comedic character will be introduced. Nardole (Matt Lucas) will be a character whose life might need some saving. “The character of Nardole is played by Matt Lucas so you can expect a lot of laughs and pathos,” Capaldi told the BBC. “He is, as ever, a hugely loveable personality, a little naïve, a little out of his depth and quite cosmic.”

5. River’s Bigamy – The Christmas special is titled “The Husbands of River Song,” and it’s easy to see how it could be a reference to the Doctor’s ever-changing appearance. However, it seems River has actually picked up another husband. In a trailer, she introduces the Doctor to her spouse, and he doesn’t seem to like the new guy.

Watch the “Doctor Who” Christmas special promo video below:

6. Russell T. Davies Was Involved – Though Davies stepped down from “Doctor Who” as showrunner in 2010, he was the one who gave Moffat the idea to bring River back. “I had sort of thought we were done with River," Moffat told the Telegraph. “But Russell [T. Davies] and I had been emailing about River. He was always saying, ‘You can’t not bring her back because she’s got to be together with [Peter] Capaldi [who plays the Doctor] – it will be a sex storm!’” The special is still family-friendly, but expect some tension between the married couple.

7. River Isn’t Staying – Though there is an opening in the TARDIS, River won’t stick around. “In a sense, the beauty of a character like River Song is that she'll come in for an adventure, but then go off again, and one can spend their time wondering what she does when she's not with the Doctor,” Kingston explained to the Bristol Post. “River's already established, so why not keep her within that respect and then bring in a new companion? Because then you've got more people to interact and play with.”

8. No New Companion – This will not be an introduction to the Doctor’s next assistant. “Doctor Who” hasn’t even cast the next traveling companion yet. “Obviously, we’ve just lost Clara so I didn’t want to go straight into a new companion, and it’s not right to set that up at the end of a series where you’re all exhausted,” Moffat told Radio Times.

The “Doctor Who” 2015 Christmas special airs Friday, Dec. 25, at 9 p.m. EST on BBC America.