In the space of an hour, the Doctor defeated death itself before Ruby finally got the answer she'd been searching for all her life.
The jury's still out on whether the ending was effective. Some fans found it underwhelming, while others thought it was brilliant.
If you have questions about how Doctor Who Season 1 Episode 8 wrapped up the season, don't worry. We're here to explain it all!
How The Doctor Defeated Sutekh
Sutekh was supposed to be one of the most dangerous villains in Doctor Who history.
He was first established in 1975's "Pyramids of Mars" (available on Britbox for those who would like to watch or rewatch it) as a powerful being from the planet Osiris who brought death and destruction before being retconned into one of the gods of the Pantheon during the current season.
Related: Doctor Who Review: The Doctor Faces Off With a Powerful Enemy
At the end of "Pyramids of Mars," the Doctor supposedly rid the universe of Sutekh by imprisoning him in a time tunnel that was too long for him to escape, but Sutekh secretly latched onto the TARDIS, allowing him to try again to destroy humanity.
Despite Sutekh's supposed omnipotence and practical immortality, the Doctor was able to set a trap for him involving Ruby's birth mother.
It had already been established that Ruby's birth mother didn't show her face at all when she left her baby on the church doorstep, which frustrated Ruby when she tried to use the Time Window to learn who this woman was. It also frustrated Sutekh.
This and everything that followed required leaps in logic, but a show featuring a time-traveling alien whose ship looks like a 1960s-era police box can get away with just about anything.
(If nothing else, this show did not rely on the same tired TV tropes we're used to on science fiction series!)
Sutekh was frustrated because he couldn't kill this woman without knowing who she was, so the Doctor used learning her identity as bait to use intelligent rope to attach Sutekh to the back of the TARDIS.
The Doctor took a triumphant journey through time and space, declaring that Sutekh would put death to death and restore the lives of all those his deadly dust had killed.
Afterward, he reluctantly cut the rope, ejecting Sutekh into the Time Vortex without the TARDIS' protection.
Doing so supposedly killed Sutekh, and showrunner Russell T Davies has stated that Sutekh is "gone forever" now.
However, there's plenty of room for Sutekh to return for a third time if Davies changes his mind or a different showrunner takes over in the future.
Sutekh is a powerful god, after all, and he escaped death by latching onto the TARDIS once, so who says he couldn't have found something else to attach himself to in the Time Vortex?
Plus, the Fourteenth Doctor's TARDIS is still parked in Donna's garden; if there are two TARDISes, there could be two Sutekhs!
Doctor Who Solved The Mystery Of Ruby's Origins
Russell T. Davies predicted that no one would guess who Ruby's birth mother was -- and he was right because she was just an ordinary woman whose story mirrored many other teenage and young adult mothers'.
Related: Doctor Who Review: Ruby's Strange Adventure
The Doctor and Ruby traveled to 2046 in the makeshift TARDIS to get the DNA sample from the database they needed to discover the identity of Ruby's mother, which led to the discovery that Sutekh had possessed Melanie and was among the dead.
During this sequence (one of the scariest moments of the hour!), Ruby stared at the DNA test results in shock, unable to believe what she saw, which suggested that she was the product of something extraordinary, such as having given birth to herself or being part Time Lord.
However, this was a red herring, and Ruby's mother turned out to be a 15-year-old girl who was terrified of getting pregnant and who lived with her abusive stepfather. Ruby soon reunited with her as an adult.
Some fans were underwhelmed with this reveal, but it underscored a point Doctor Who often makes: everyone is important, no matter how ordinary they are.
According to the Doctor, Ruby's focus on finding her mother triggered Sutekh's obsession, believing she must be someone with extreme powers if she was so important to Ruby. Thus, he became determined to find her, which led to his downfall.
She was important because we thought she was important. That's how everything happens. Every war, every religion, every love story. We invest things with significance. So while the whole of creation was turning around her, it made her sheer existence more powerful than Time Lords and gods. In the end, the most important person was the most ordinary. A scared little girl making her baby safe.
The Doctor
It also led to Ruby leaving the TARDIS. Millie Gibson has been confirmed for Season 2, so Ruby will be back, but for now, she and the Doctor shared a sad goodbye before what looked like a disappointing character exit.
After Ruby told him that she wanted to leave again with him, she learned that her family had contacted her birth father, who never knew she existed.
The Doctor told her that her place was with her family but promised he would return to visit.
His promise that he would be ironic, considering Ruby's fear that he would abandon her as he did his granddaughter, Susan.
Related: Has Doctor Who Set Up a Possible Torchwood Return?
In 1964, when the Doctor locked Susan out of the TARDIS because he felt she belonged on Earth with the man she fell in love with, he promised he would be back "one day."
The similarities between that ending and Ruby's apparent exit suggest that the Doctor may be leaving her temporarily to fulfill that long-ago promise to Susan.
Doctor Who's Final UNIT Scene Explained
After everyone was resurrected, the Doctor returned to UNIT to check on his friends and to run the DAN test so that RUby could learn the truth about her birth mother.
This short scene set up future UNIT stories.
Rumors have been circulating about a UNIT spinoff, and this scene established who would star in such a show.
In addition to Kate, Rose, Melanie, Donna (presumably, since Rose said her mother also works for UNIT), and Colonel Ibrahim, Kate recruited Susan Triad.
The most confusing part of this scene was the reveal that Susan Triad was a real person with real memories, as Sutekh had explained that he used the TARDIS' memories of the Doctor's granddaughter to create duplicate versions of Susan wherever the TARDIS landed.
However, if you listen carefully to his explanation, he also reveals that each of these people was real, fitting into history wherever the TARDIS landed.
He merely possessed them all so that when the time was right, they became the living dead, spreading his fatal dust throughout the universe.
The Internet is abuzz with whispers about Colonel Ibriham taking Kate's hand at the end of the scene. This could indicate that love was in the air, but most likely does not.
Colonel Ibriham also ran to hug Rose after everyone was resurrected, so he may have been extra affectionate because he was so relieved everyone was all right.
It's also too bad that Catherine Tate was unavailable for a short cameo during this scene.
I'd have loved for her to yell at Kate about how UNIT was supposed to keep her daughter safe, but Rose was briefly turned to dust while doing her job.
Colonel Ibrahim also shares a name with someone Sutekh possessed during "Pyramids of Mars," but hopefully, that's a red herring. Since Sutekh is gone for the foreseeable future, there's no reason for Ibriham's name to mean anything.
Doctor Who Set Up Some Mysteries for Season 2
The episode's ending was noteworthy for what it didn't tell us. Many viewers were frustrated and disappointed that Mrs. Flood's true identity had not yet been revealed.
She told Cherry Sunday that she had had "such plans" for her right before the fatal dust got them both, suggesting that she was someone evil.
Related: Cliffhangers That Made Our Jaws Drop To The Floor
At the end of the hour, she broke the fourth wall, informing the audience that she was sorry to say that the Doctor's story would end in absolute terror.
These are the strongest clues to her identity so far, and Russell T Davies has already promised we will learn more about her during Season 2.
There is already a ton of wild speculation online around who Mrs. Flood is, with fans guessing everybody from Clara Oswald to River Song.
Mrs. Flood could also be the amoral Rani (a renegade Time Lord who has not appeared in years due to questions over who owns the rights to the character) or Missy, the female version of the Master.
Over to you, Whovians!
Are there any lingering questions from the finale we haven't explained yet?
Who do you think Mrs. Flood is?
Do you think there's more to Ruby's origin story than we've gotten so far?
Hit the comments and let us know!
Doctor Who Season 1 streams on Disney+.