Under the direction of head of projects Dastari, Kartz and Reimer had been conducting experiments in time travel aboard Space Station Camera, finally building a primitive time capsule called the Kartz-Reimer module. Their work was advanced, but the final secret to making the machine function eluded them. The Kartz-Reimer experiments had begun to affect the space-time continuum, attracting the attention of the Time Lords, who sent the Second Doctor to advise the scientists to halt their experiments to avoid further damaging the continuum. Dastari, his Androgum servants Chessene and Shockeye, and the Sontarans Stike and Varl with whom they were secretly working murdered everyone aboard the station apart from the Doctor's companion Jamie, who escaped into the station's substructure. They falsified evidence implicating the Time Lords in the attack and abducted the Doctor to Earth, bringing the Kartz-Reimer module with them, in order to extract the final secrets of time travel and get the module working.
The abduction of the Second Doctor was psychically felt by the Sixth, who went to Camera and found Jamie among the wreckage. The Sixth Doctor, Peri Brown, and Jamie travelled to Dastari and the Sontarans' base in an old hacienda outside Seville, Spain to rescue the Second Doctor, and in the course of events the Sixth Doctor and Jamie encountered the Kartz-Reimer module in the hacienda's cellar. The Doctor marvelled at how close the module was to a working time machine. Aware that Stike was covertly listening, the Sixth Doctor explained to Jamie that the machine would never function without a Time Lord taking the first trip, priming it with the Rassilon Imprimatur. Stike then revealed himself and forced the Doctor into the module to prime it; the Doctor took the opportunity to sabotage the module by removing the interface of the briode nebuliser. Afterward, Chessene, Dastari, the Androgums, and the Sontarans moved forward in their various plans.
Later, after the deaths of Dastari, Shockeye, and the Sontarans, Chessene forced Peri to take a trip in the module to demonstrate its functionality after the Doctor returned the stolen briode nebuliser. Satisfied by Peri's safe return that the module was now fully functional, she attempted to use the Kartz-Reimer module to escape. However, the Doctor had sabotaged the nebulizer before he returned it to them, leaving a thin membrane so that it would make one effective trip to protect whichever of his companions Chessene chose to use as a test subject, and the module exploded, killing her. (TV: The Two Doctors)