Nardole brings Bill Potts into the Doctor's office and offers her a smith. His arm whines as he gestures, and a bolt falls out. He nudges it under a chair and steps out, and Bill notices the police box in the corner with an "out of order" sign on it. As Bill sits down, a burst of guitar music emerges from the next room. Bill coughs and the Doctor comes in after a moment. He points out that she's not a student at the university but she comes to his lectures, and wonders why she comes there. Bill says that she works in the canteen and talks about how she gave a girl she liked extra chips until she got fight. She asks about the TARDIS, pointing out that it's too large to fit through the office door or windows. The Doctor claims that he had it lifted in with a crane and repeats his question, and Bill says that she likes them. She wonders why he noticed her, and the Doctor says that Bill smiles when she doesn't understand something.
Bill points out that some people say the Doctor has been there for over 50 years, and wonders what he lectures on. The university apparently lets him do whatever he wants, and Bill says that she always wanted to come there. As she goes, Bill tells her that she's now his student and she should never be late for his lectures. As she goes, Bill wonders what she calls him. She points out that "the Doctor" isn't a name and asks "Doctor what?"
The Doctor gives a lecture about the passage of time.
Bill goes about her day working at the canteen and gives extra chips to the girl. She attends the Doctor's lecture and goes to his office afterward. She goes to a bar and notices a girl from the lectures looking at her. They bump into each other in the crowd and stare at each other.
One day Bill is walking across the campus and sees the Doctor and Nardole walk off together. She follows them to a basement and discovers the door is locked. The door opens for her and Bill goes in, and hears Nardole warning the Doctor that he's not suppose to get involved as they examine a vault door. When she bumps into something, they hear her and glance over, and Nardole says that he set the security on the door to "friends only."
Bill goes out and sees the girl, Heather, sitting on a bench alone. She sits down with Heather and asks about what's in her eye, and Heather says that it's a defect in the iris that looks like a star. Bill starts to go and then asks if Heather is freaking out about something. Heather asks her to come with hr so that she can show her something, and Bill immediately agrees. They go to a new dormitory and Heather points out a puddle even though it hasn't rained in a week. She asks Bill to look into it, and Bill goes over. Heather asks if she can see what's wrong with the reflection, and Bill realizes that her reflected face is wrong. Heather walks off, telling Bill some other time.
Somewhere, a voice says that Violet is contacted and link is established as the speaker looks through the reflection.
Come Christmas, Bill brings the Doctor a present. It's a rug, and they have Christmas dinner. The Doctor claims that he doesn't go anywhere for Christmas. Bill figures that he's gone lots of places, and talks about how her mother died when she was a baby.
At home, Bill's aunt Moira finds some photographs of her as a child. Bill looks through them and cries, and finds one of her mother... and a mirror reflecting the photo taker: the Doctor.
When the new term starts, Bill goes to the Doctor's office and notices that the rug she gave him is now under the edge of the TARDIS.
As Bill goes past the dormitory, she sees Heather looking at the puddle. She offers to show Bill what was wrong with her reflection. When Bill goes around the fence, she discovers that Heather is gone. She walks off, unaware that Heather's horrified face is staring out of the puddle.
Bill goes to the Doctor's office and he realizes that something is wrong. She describes the star in Heather's eye and says that there was something wrong with the reflection in the puddle. Bill looks out the window and sees the Doctor running off, and goes after him to the dormitory. The Doctor is staring at the puddle, and Bill wonders if the star in Heather's eye has something to do with the puddle. Bill wonders if Heather is possessed, and the Doctor realizes that Heather could notice the discrepancy because her face is asymmetrical. He explains that Bill's reflected face looks wrong because it shows images the right-way around. The Doctor takes a sample of the "water" and realizes that it's not water, and notices scorch marks around the puddle. He then tells Bill that the class is off and dismisses the puddle as a freak optical effect, and claims that he's bored already.
The watcher says that the passenger is selected and pursuit is engaged. The puddle spreads out.
Bill returns home and hears water running in the bathtub. She knocks on the door to let Moira know that she's there and goes to the kitchen. Moira calls and says that she's at a bar, and Bill wonders who is taking a bath. The faucet turns off and Bill goes to investigate. When no one responds to her calls, Bill grabs an umbrella as a weapon and opens the door. The bathtub is wet but empty, and she sees a silhouette in the shower. Bill yanks aside the curtain but there's no one there, and water going down the drain. An eye looks up at her from the drain and Bill runs out to the street.
When Bill goes to the university she sees the Doctor through his office window. Heather is standing nearby, dripping wet. Bill talks to her, and Heather repeats her word, and Bill says that she's dead. Heather lunges at her, and Bill runs up to the Doctor's office and barricades the door. Water pours under the door and forms into the shape of Heather. The Doctor stares at it, intrigued, and then leads Bill into the TARDIS. He assures her that nothing gets in, and turns on the lights to reveal the vast interior. Bill finally notices and the Doctor tells her that she'll always be safe inside. Bill says that it's like a really posh kitchen and asks to use the toilet.
Nardole comes in and tells the Doctor that they have a human aboard. The TARDIS shakes and the Doctor explains that they're under attack. He dematerializes the ship and then rematerializes it, and they go out. They're in the basement, and the Doctor confirms that the vault is secure. Bill finally works out that the TARDIS isn't a kitchen. The Doctor says that he wants to make sure the creature isn't there for what's in the vault, and Bill points out that it's been there for ages and wouldn't have laid around for a puddle if the vault was there. The Doctor isn't convinced.
They hear water moving at the door, and the Doctor tells everyone to move toward the TARDIS. Water flows down the stairs and forms into Heather, and she screams. The Doctor gets everyone into the TARDIS and figures that the creature wants to kill them rather than get what's in the vault. He takes the TARDIS to a dock a boardwalk in Australia during the day, and Bill follows him. Once she realizes that they've moved in space, she goes into a nearby bathroom to rinse off her face. The Doctor comes in and asks how he can help, and Bill asks if he's from space. The Doctor explains that he's from a planet but not Earth, and Bill wonders why the TARDIS is named in English.
Water forms on the mirror and Bill and the Doctor run out into the restaurant as Heather comes out behind them, screaming. In the TARDIS, the Doctor takes them as far as they can to see how long it will take Heather to follow them. They go 23 years in the future and step out onto a barren planet. The Doctor suggests that the scorch marks were from a shuttle, and it left a leak of intelligent oil behind. He figures that it saw something in heather that it needed, and Bill remembers Heather saying that she wanted to leave. The Doctor suggests that the puddle wanted to leave and found Heather, so it ate her.
Bill notices a puddle nearby, and Heather's face appears in it. She smiles and then grabs Bill, and the Doctor and Nardole pull Bill away as the water gushers out. They get back into the TARDIS and the Doctor takes it that they'll run the water creature through the deadliest fire in the universe... by going through it first. He tosses Nardole a sonic screwdriver and tells him to run interference, and explains that they're in the middle of a war zone.
The Doctor says that he has old friends there and leads Bill outside. Daleks shriek that the Doctor is detected, and the Doctor leads Bill through the wreckage and Nardole yells at him to keep moving. Movellans are shooting at the Daleks and get blasted down, and Heather appears in the corridor. Running, the Doctor and Bill come to a Dalek. The Doctor tells it to identify him, and says that he's an enemy of the Daleks. He pulls Bill out of the way as the Dalek fires, hitting Heather. The blast has no effect, and the creature echoes the Dalek's words to exterminate.
A Dalek finds Nardole and opens fire, and he runs.
The Doctor and Bill run until a Dalek cuts them off. It stutters and the Doctor approaches it, curious. Nardole arrives and says that he's quarantined the area, and the Doctor points out that the Dalek's eye iris is star-shaped. Bill realizes that it's heather, and the "Dalek" starts dripping water. It reforms into Heather, and the Doctor asks why it didn't use the gun it had. He says that he won't let the creature take someone else from Earth and tells it to leave. "Heather" looks at Bill, and Bill remembers Heather promising that she wouldn't go without her. She says that she understands, and explains that the creature is acting on Heather's crush for her. The Doctor warns that the creature is inviting Bill to come with her, and tells Bill to release her from her promise.
Bill goes over and tells the creature that it has to let her go. When it echoes her words, Bill says that it will and the creature repeats her words and steps back. Bill tells it that she really liked her, and they extend their hands. The Doctor and Nardole tell Bill not to do it, but they touch fingers and Bill sees all of time and space from the creature's perspective. The Doctor warns Bill that it's a trap, and warns that "Heather" isn't human anymore. Bill says goodbye to Heather, and it says "Goodbye, Bill." As the creature dissolves and fades away, the Doctor pulls Bill back. He asks if she's all right, and Bill says that she is. She cries, but the Doctor doesn't notice and Bill says that they're not her.
Back on Earth, the Doctor says that the vault alarm went off but it was nothing. Bill says that she saw everything out there through the creature's memories, but she was too scared to accept its invitation. The Doctor tells her that scared is rationale, and figures that they won't see it again. Bill glances at the TARDIS, and the Doctor tells her to forget it. When she warns that she may not be able to, the Doctor reaches for her head and Bill figures that she's going to wipe her memory. He insists that no one can know about him because he's there in disguise, and Bill asks him to let her remember for one night and have some good dreams for once. She finally gives in and tells the Doctor to do what he has to do, but asks him to imagine what he'd feel like if someone did it to him. After a moment, the Doctor gently punches her on the chin and tells her to get out before he changes his mind.
As Bill goes, she remembers everything that happened to her. She runs out and finds the Doctor waiting by the TARDIS. He says that it's a big universe and maybe one day they'll find heather. Bill asks what changed his mind, and the Doctor says that the TARDIS did it. The door opens on its own and the Doctor goes in... and Bill runs after him.
Written by Gadfly on Apr 16, 2017