Heathcliffe Bower is a frustrated Conservative politician. The former actor has been disappointed in his political ambitions and blames the Prime Minister, Margaret Thatcher. He makes plans to assassinate her.
Heathcliffe obtains a gun and makes arrangements with the party to have Thatcher appear at a summer fete. After she arrives by police escort, Heathcliffe shoots her, killing her with the first bullet.
The Doctor, Tegan and Turlough are visiting Earth. Tegan spots a newspaper headline "Thatcher Assassinated". The Doctor is concerned; Thatcher is not supposed to be assassinated. There could be drastic consequences to space/time.
The TARDIS takes them to the time of the assassination. However, they land some distance away and have to walk to the site. As they arrive, Heathcliffe is about to pull the trigger. The Doctor sprints towards Heathcliffe, but the police see him as a threat and stop him, arresting him. Heathcliffe succeeds in his assassination.
The Doctor, after a "well-placed phone call", is freed from prison, and the trio try Plan B. History doesn't even record the assassination attempt, so they must go further back. They visit Heathcliffe in the days before the attempt and try to convince him not to go through with it, but their attempts fail.
Plan C involves taking Heathcliffe out of prison and bringing him back in time to meet his young self. They visit Heathcliffe while he is still an actor, before he became a politician. They find him at a bar. The Doctor introduces him to a young, unmarried Thatcher. The older version of Heathcliffe talks to his younger self over tea and tells him of his future.
In the end, the Doctor has succeeded in undoing the assassination. The younger Heathcliffe does become a politician, but eventually retires and spends his days gardening with Daphne and walking his dogs. The Doctor expects that the older Heathcliffe will just disappear, but when that doesn't happen, the Doctor takes him to the time vortex.
- Heathcliffe mentions the murder of John Lennon and the assassination attempts against Ronald Reagan and the Pope.
- Heathcliffe mentions the Falklands War.
- The Doctor mentions that the president of the United States was an actor. Heathcliffe tells him President Carter was a peanut farmer, but has a vague memory of an actor opposing Gerald Ford in a recent nomination.
- Heathcliffe thinks he has been reading too much Ray Bradbury and Philip K. Dick.
- Heathcliffe uses the Doctor's celery to stir his Bloody Mary.
- The version of Heathcliffe that didn't assassinate Margaret Thatcher occasionally appeared on Wogan, giving anecdotes.
- Each story in Short Trips: Repercussions includes a character or characters being taken out of their time by the Doctor to avoid harm to the Web of Time. In this story, it is Heathcliffe Bower.
- This story is partly narrated by Heathcliffe and partly told in the third person.