The Doctor and Ruby land in Wales. The Doctor can tell where they are from the smell of the sea air. He starts to tell Ruby about a terrible Welsh Prime Minister but realizes he's talking about her future.

Ruby accidentally steps on something (again). It looks like a circle has been built here, possibly by children. The Doctor picks up the flowers and apologizes. Ruby reads some messages and realizes it's a memorial to someone called Mad Jack. She looks up and the Doctor is gone.

Ruby assumes he's in the TARDIS but it's locked and her key won't work, and the Doctor is not around outside anywhere. The only other being she sees is a mysterious figure, white, with a black robe who keeps beckoning to her (reminiscent of the Watcher in Logopolis).

Ruby runs down a hill, scared. The random snow that seems to keep following her begins. A hiker (Susan Twist's latest character) sees her and asks if she's okay. Ruby asks the hiker to tell this woman that she's fine and stop following her. She also thinks the hiker looks familiar. The hiker approaches the mystery woman and screams.

Ruby runs all the way to town and goes into a pub. The barkeep doesn't seem to like her. Ruby rambles about the woman following her and asks to pay with her phone. The barkeep doesn't know what she's talking about and then when she shows her says sarcastically that of course she can.

A patron named Josh goes to talk to the woman following Ruby and screams and runs away.

Ruby mentions the structure she stepped on by accident. An old woman in the pub says it's a fairy circle and that the clifftops are a magical area where rules are suspended.

Ruby tells them about the scrolls she read. The old woman says Mad Jack's soul has been unbound now and he will kill them all. There is a pounding on the door. They are all spooked except Ruby who says this is not Mad Jack.

Ruby opens the door to a delivery guy. Everyone laughs and says they really had her going. The old woman says it's racist to think everyone in Wales is a witch or druid. Ruby goes outside and sees the mysterious figure.

The next morning the barkeep gives Ruby some clothes and says she wants them back later.

Ruby goes and looks at the TARDIS but to no avail. She goes back to the Pub and the barkeep says Josh won't come back because of her so she kicks her out.

Ruby decides to go home. She tells the TARDIS she'd like to see the Doctor again if he ever returns. She takes a train back to London and Carla is thrilled she is home and says men are all the same, puttering around in their sheds. 

Ruby tells Carla about the mysterious figure. Carla decides to call Ruby and then go talk to the woman so Ruby can see what she says. Mrs. Flood sees and thinks it's strange then goes back in her house. Carla tells Ruby the woman is what she looks like. She screams and runs away.

Ruby sees Carla in the back of a car, glaring at her. She collapses in the street, sobbing, as Carla disappears. Carla won't come back and tells Ruby to stop calling and says no one wants Ruby, not even her real mother.

A year later, Ruby meets Kate Lethbridge-Stewart who is sure they can help. However, when Kate has UNIT try to capture the mysterious figure, she suddenly turns against Ruby too and runs away.

The years go by. Ruby attempts for the next 20 years to have a normal life. She turns 30, then 40, alone because her dates notice something off about her and the apparition is always in her yard.

Ruby is in a bar on another date. She is now in her 40s and wearing glasses. She sees Roger Ap Gwilliam on the telly at a debate. He says they used to call him Mad Jack. The old woman warning her about Mad Jack comes back to her.

Ruby decides she knows what she must do. She tells her boyfriend she has to save the world and leaves.

Ruby volunteers for Roger Ap Gwilliam's campaign, willing to do anything. She hears him on an interview saying that he wants to use nuclear weapons and ignore NATO protocols.

Roger notices another volunteer and Ruby tells him that's Marti Bridges. He thinks it's odd that Marti has a boy's name.

Roger wins the election and plans to take control fo the nuclear codes during the transition. Ruby goes out on the pitch, which is illegal, and goes exactly 73 yards so the apparition messes with Roger. He runs away and resigns from Parliament. Ruby thinks that's done and the apparition can leave her alone now.

40 years later, an 85-year-old Ruby's aide brings her back to where the moss has gathered on the TARDIS and she realizes the Doctor wanted her to have hope.

A very old Ruby is in hospice care. The apparition comes to her in the night. She flashes back to when Ruby was young.

The old Ruby is revealed to be the apparition, watching as Ruby and the Doctor get out of the TARDIS in 2024. She whispers, don't step, don't step... 

Ruby sees the apparition but the Doctor doesn't. Ruby stops the Doctor from stepping on the fairy circle. He suggests Ruby leave the circle alone and asks her when the third time she went to Wales was.

She says right now.