Ep 1. The Husbands of River Song

The Doctor Who Christmas Special for Season 4, Episode 1 is titled "The Husbands of River Song". This episode is a standalone story in the Doctor Who universe, and does not involve any overarching plotlines from the regular season. The episode follows the 12th incarnation of the Doctor, played by Peter Capaldi, as he teams up with the notorious time traveler, River Song, played by Alex Kingston.

River Song is a character that has been featured in several previous Doctor Who episodes, and is known for her complex relationship with the Doctor. In "The Husbands of River Song", the Doctor finds himself reunited with River on the planet of Mendorax Dellora. River is on a mission to steal a valuable diamond, and enlists the Doctor to help her in the heist. However, the Doctor soon discovers that River has been married multiple times, and that he is not the only husband that she has had.

The episode features several comedic moments as the Doctor tries to navigate River's past relationships. The Doctor's interactions with River's various ex-husbands, including a robotic surgeon and a ruthless warlord, provide plenty of laughter and adventure.

The plot thickens as the diamond that River is after turns out to be a trap set by a group of dangerous aliens. In order to escape with their lives, the Doctor and River must work together to outsmart the aliens and their deadly devices. Along the way, the pair must confront their feelings for one another, and come to terms with the fact that their time together may be limited.

Overall, "The Husbands of River Song" is a fun and exciting Christmas Special episode that showcases the unique chemistry between the Doctor and River Song. The episode provides plenty of laughs and action, while also exploring the complexities of the Doctor's relationship with his time traveling companion. Fans of the show will enjoy this standalone episode, which is both entertaining and emotionally satisfying.