Just like the first chapter, the finale of Flux was a crowded set of plotlines trying to finish. It boiled down to two things: Swarm wants the universe and the Doctor destroyed, and some bad guys wanted to use the Flux to be invincible. Did they succeed?

SPOILERS BELOW

The overall story was very interesting, based on how two creatures tried to destroy everything because of a past so secret even the Doctor doesn’t know it…and it’s hers. Too bad it didn’t end as well as it should have.
The first and last episodes had too much plot jammed into an hour. It would have been better to stretch this out to eight episodes to give all the plots more time to breathe.

The Doctor is about to be destroyed, maybe way too slowly, by Swarm (Sam Spruell) and Azure (Rochenda Sandall) , while the Sontarans are about to attack Earth at several time zones.
She tries to escape by taking off her conversion badge, but Swarm grabs her at the same time. For much of the show, she is split in three. Having more than one Doctor, even in parts, is a nice trick. It’s just a matter of literally keeping it together. At least she can organize her fam back.

As we said before, it boils down to two main plots. First, Azure and Swarm want to destroy the universe with the Flux, then rerun it like it’s on a DVR. It’s their revenge over the Doctor deserting them and Division.
Second, the Sontarans want surrender of Earth with “benefits”. They even want to make friends with the Daleks and the Sontarans, which seems odd. The Grant Serpent (Craig Parkingson), meanwhile, wants to double cross the Sontarans so he can claim the Earth. That won’t fool everyone, especially Kate Stewart (Jemma Redgrave) of UNIT. More on this later.
Williamson (Steve Oram) admits he discovered warps in the time continuum as he was digging under Liverpool, and set up tunnels to various places and centuries. He’s forced to sacrifice them to the Flux, but at least he’ll be remembered for other reasons.

Swarm and Azure spend too much time taunting the Doctor, vowing revenge while offering her the Gallifreyan Fob Watch that has all her redacted memories. If they hoped to tempt her with this, it didn’t work very well. What worked better was how they showed they could destroy the universe and her body, since she is the universe. It’s telling they hate life because it took up space.

Meanwhile, the other parts of the Doctor were busy trying to stop the Sontarans and getting Jericho (Kevin McNally) and Claire (Annabel Scholey) back from the past. Those two were especially important because she wants them to infiltrate the Sontarans. They soon learn the aliens want to know when the final Flux event will happen, and use their psychic talents to do that.
This is actually a better plan than what Swarm wanted: the Sontarans use the Flux to kill the Cybermen and Daleks, and become the dominate alien race.

Karnavista (Craige Els) spends much of the time getting annoyed, and is also angry that his kind was killed by the Sontarans to use their shields to protect from the Flux. He also admits he worked with The Fugitive Doctor, but would rather poison himself than talk about it. She wonders if he was her Companion, but he only says she deserted him. It shows not all relationships with Companions end well, mainly the ones before 1963. Maybe that’ll be discussed again.

Meanwhile, Vinder (Jacob Anderson) and Diana (Nadia Albina) are still stuck in the Passenger prison, but she discovers a lot of flaws in it.  It’s too bad we didn’t have more of this, but the story only had six episodes. They do get out before they get recaptured, but send a signal to the TARDIS to fully escape.

Then it gets complicated. When the Sontarans use the Flux, a lot of Cybermen and Daleks are killed. However, the Sontarans’ shield collapses because Karnavista knocked out their forces and hijacks the Lupari ships. This leads to a victory that is uncomfortable for some. Still, the Sontarans thought of it first.
They also get rid of what’s left of the Flux by sending it into the Passenger.
However, Jericho sacrifices his life in the battle. This is too bad, because he would have made a great recurring character.

Eventually, it ends at Antropos as Swarm and Azure bring the Doctor to Antropos and Time itself. It looks like Swarm, and it’s not happy. It gets rid of Swarm and Azure much too easily. It’s really an anti-climax after weeks of getting everything they wanted. It lets the Doctor go (while taking her form). However, it warns her that it’s soon the end of her (and not just because she’ll undergo changes next year), and warns her of evil forces and their master. That may might mean Sacha Dewan is coming back, and he is due for a return visit.

Karnavista leaves, but with Bel and Vinder. He’s not happy about this, but he might be later. Claire is sent back with Kate, who hopes to see the Doctor again very soon (and we hope to see UNIT again). The Grand Serpent is moved to a very isolated place, but who’s to say he’ll try to “ally” with someone else? It’s too bad Vinder didn’t really get a lot of revenge against him, but it may suggest it’s not over between them.

Dan is back at the museum, but is still trying to have some relationship with Diana. She’s not interested, for now anyway. At least he can still hop on a TARDIS for a little longer.
After apologizing to Yaz for keeping her in the dark about Division, the Doctor hides the fob in the TARDIS control, where she won’t be tempted to look at it. At least for now.

The overall story was interesting, but it tried to do too much with too little time. At least it showed proved Jodie should be recognized as a classic Doctor. Yaz also had a lot of things to do. A spinoff with her (maybe in UNIT?) or Karnavista’s new crew should be considered.

The Doctor will return New Year’s Day as two people in a storage unit have a very interesting holiday. It involves a time loop and the Daleks.