The TARDIS materialises in an underground cave during an earthquake. The Doctor and Jo escape the TARDIS just in time as it falls into a crevice. They are surprised to see the TARDIS reappear and fall again, and the Doctor realises it's caught in a time loop.
The Doctor and Jo climb out of the cavern and find themselves in 1950s Greece. At a taverna, the Doctor notices a man sitting at a nearby table, while Jo notices a good-looking man at the bar. The Doctor suddenly heads for the first man's table and accuses him of being a Time Lord. The man, Katsoudas, agrees, and shows the Doctor and Jo a device on his table that causes time loops. He activates it, and the good-looking man at the bar repeats his actions of talking at the bar and leaving it, before ending up back at the bar.
Katsoudas explains that he is on a mission for the Time Lords, who imprisoned criminals in a time loop which has now gone wrong. They need the Doctor's help, and it was they who brought him here. Katsoudas is pretending to be a seismologist studying the prediction of earthquakes. He turns off his time loop device, and the good-looking man, introduced as Katsoudas' assistant Nikos Spiridakis, joins them.
The four of them head for Katsoudas' dig site. Spiridakis and Jo take a lift underground, while the Doctor and Katsoudas enter the building that houses the equipment. The Doctor wonders at the sophistication of the equipment, and Katsoudas explains that his patron, Senator Szef, funded the equipment. Katsoudas also explains that he is able to predict earthquakes because he is the one causing them.
Katsoudas starts an earthquake, which damages the lift shaft. Spiridakis is unconscious, and Jo leaves the lift to look for help in the cavern. She is left behind when the lift ascends, brought to the surface at the Doctor's insistence. A large creature approaches Jo. However, she soon realises that the creature, which is wearing a spacesuit and coming out of a spaceship, is going through a time loop and resets before it can see her. This happens several times, and Jo is feeling a bit bored, when suddenly a voice addresses her by name.
The Doctor is appalled at Katsoudas' actions and worried when the lift brings back only Spiridakis. He wishes to meet Senator Szef, who now appears on the scene. The Doctor realises he should have expected that Szef was in fact the Master. He is accompanied by Jo, whom he has captured.
The Doctor realises that Katsoudas is not actually a Time Lord, but was hypnotised by the Master. The Master explains his situation. He is trapped in the area of the time loop, along with the Odobenidan crew of a spaceship. He is using earthquakes to try to free the ship, heedless of the damage it will do to Earth's Mediterranean region.
As the Doctor distracts the Master, Jo drags Katsoudas to the TARDIS. She tries to get Spiridakis to come with her, but he heads for the controls of the Master's equipment. The Master sees him and tries to stop him, but when he fails, he leaves in his TARDIS. Spiridakis has managed to confine the earthquake's effects to the immediate area, but the temporal equipment ages him to death. The Doctor heads for the TARDIS, where Jo and Katsoudas are waiting, protected from temporal damage.
Katsoudas boasts that he has been free of the Master's control for some time, and that he plans to continue his work, using the alien equipment. However, the Doctor will not allow it, and removes Katsoudas from his own time to preserve the Web of Time.
- The Doctor comments that the Brigadier is in Palestine at this time.
- The Doctor and Jo drink ouzo.
- When Jo tries to speak Greek to the waiter, she asks for a kilo of peaches.
- Katsoudas claims to have been sent by the Time Lords.
- 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 Professor Katsoudas.