Zeitgeist (short story)

Zeitgeist was the tenth story in the anthology Decalog 3: Consequences. It was written by Craig Hinton. It featured the Fifth Doctor and Turlough.

Summary
The TARDIS is forced off course and materialises on the planet Heracletus, and the Doctor theorises that the Time Lords need him to fix something for them yet again. However, when he and Turlough step out of the TARDIS they find themselves in separate timelines, cut off from the TARDIS. The Doctor finds himself in a technologically advanced culture where scientist Enryk Ullius, with the help of the late alien Ambassador Ts’ril, has created the Spline, a chronon stream with which he can plunder resources from the future and save his dying planet. Turlough, however, is in a world where Ullius is the High Priest of a cult which worships the Spline -- and an alternate version of the Doctor is also present, this version an arrogant Time Lord agent called the Savant. Turlough discovers that Ullius’ cult has been discarding advanced weapons, unaware of their significance, and he leads a group of rebels led by Festle Caloon into Ullius’ temple; however, they are betrayed by a double-agent and captured. Turlough tricks Ullius into firing one of the weapons into the Spline, triggering an energy backlash. Meanwhile, the Doctor also meets Caloon -- but his version is a scientist working for Ullius, and when he learns that the Doctor is also an alien he lets him examine the Spline. Ullius is furious when he finds the Doctor tampering with his work, even more so when the Doctor reveals that the Time Lords have already placed Heracletus in a time loop to prevent Ullius’ work from damaging history. Determined to break through the loop, Ullius boosts power to the Spline, triggering an energy backlash. The Doctor’s and Turlough’s timelines thus overlap, and the arrogant Savant’s attempts to put things right cause the timelines to begin collapsing into each other. The Doctor realises that the time loop was flawed; each time Heracletus reached the end of its four-year cycle and began again, its history was slightly different. He, Turlough and the TARDIS have been caught in the time loop, and the Spline is an alternate version of the TARDIS itself. The Doctor is able to home in on the actual TARDIS’ location and transport himself and Turlough to safety, but in this version of reality, Heracletus is a desert wasteland where all life was destroyed by the Heracletes’ failed time-travel experiments. The Doctor and Turlough depart, knowing that the time loop will soon collapse into a time rift -- which the Doctor suspects he’s already dealt with...

Characters

 * Fifth Doctor
 * Vislor Turlough
 * The Savant
 * Enyrk Ullius
 * Festle Caloon

Worldbuilding

 * Sontarans do not sweat.
 * The TARDIS can only be manipulated by the Matrix or another TARDIS, but enough safeguards are in place to prevent another TARDIS from influencing her too much.

Continuity

 * Turlough reflects on Tegan's departure from the TARDIS in TV: Resurrection of the Daleks, also on events of PROSE: Lords of the Storm and his time working for the Black Guardian. (TV: Mawdryn Undead, Terminus and Enlightenment)
 * The Doctor was made Lord President of Gallifrey in TV: The Five Doctors.
 * The time rift that the time loop collapses into is the same one seen in PROSE: ...And Eternity in an Hour.
 * The Doctor remembers meeting Ts’ril in PROSE: Timevault, and speculates that their discussion of the TARDIS workings at that time may have inspired the Spline.