The Doctor has escaped his pursuers, or so he thinks, and finds himself in England in the middle of nowhere. A man in a car, giving his name as Marcus Johns and saying he is a physics master, offers the Doctor a ride. They have a flat tire, and when Johns gets out of the car to fix it, he starts to push the car off a cliff. The Doctor escapes in time, realising that his pursuers have acquired the ability to shape shift.
The Doctor makes his way to nearby Denby prep and encounters Edward. He poses as the new physics master. Only Edward and the Doctor seem to be aware that today is Sunday, just like yesterday was.
The Doctor explains to Edward that he is fleeing aliens who consume the inner life force of their victims. He warns Edward that they will find him at the school. He tries to explain the situation to the headmaster, Mr Milligan, but Mr Milligan isn't convinced and the Doctor has to pretend that he is with the British government and a German invasion is imminent.
As the school prepares for the invasion, two shapeshifters invade the school. The Doctor suddenly realises that not only can the aliens not touch him, they also are tapping into his darkest fears. With this realisation, he confronts one of the aliens and walks past it. He urges Edward to do the same with the other alien. The two aliens evaporate without a trace.
The Doctor says goodbye to Edward, promising him that he will see him again.
- The Doctor pretends to be the new physics master.
- The stories in Short Trips: The Centenarian revolve around Edward Grainger, a man who has met the Doctor more than a dozen times over the course of his life.