Regeneration Operation

The Regeneration Operation was 's name for his failed attempt to steal the Eighth Doctor's remaining regenerations. (PROSE: The Secret Diary of the Master, TV: Doctor Who)

Background
In, a man with "saturnine features", (TV: Doctor Who, PROSE: The Novel of the Film) the Master eventually arrived in the Valley of the Kings in Egypt and was captured to be placed on trial (AUDIO: Mastermind) by a Dalek scouting party. (PROSE: Dalek: The Astounding Untold History of the Greatest Enemies of the Universe) Another account claimed that the Master's trial by the Daleks took place immediately after his experience on the Cheetah World, with still in his stolen Trakenite body and maddened by the cheetah virus. (PROSE: The Eight Doctors)

At any rate, the Master was indeed tried in the presence of the Dalek Emperor (PROSE: The Novel of the Film) and the whole Parliament of the Daleks, (PROSE: The Runes of Fenric) for his attempts to destroy them and usurp their place as "the supreme creatures of the universe", (PROSE: The Novel of the Film) specifically with regard to his failure in their mutual plot behind the Human-Draconian War, (PROSE: The Runes of Fenric) while encased in a painful column of light which prevented him from moving; (PROSE: The Novel of the Film) it was "said" that he stayed oddly impassive as his long list of crimes was read out to him. In truth, this was all a ruse to get inside the Doctor's TARDIS and further extend his precarious existence. (TV: Doctor Who)

The Dalek Litigator judged the Master guilty, ordering him to be exterminated as his punishment. (AUDIO: Vengeance) After he was tried and executed by the Daleks on Skaro, he made a final request: for the Seventh Doctor to transport his remains back to Gallifrey. (TV: Doctor Who) According to one account, he made this request via telepathic contact with the Seventh Doctor, even as he was about to be discorporated, and the Daleks never knew of his demands, which the Doctor fulfilled covertly by sneaking into the Dalek bastion. (PROSE: The Novel of the Film) According to other accounts, it was as part of a Time Lord-Dalek treaty (PROSE: Lungbarrow) called the "Act of Master Restitution" (PROSE: A Brief History of Time Lords, Meet the Doctor) that the Doctor was able to safely journey to and from Skaro to retrieve the Master's remains. (TV: Doctor Who)

The incident
To be added

Aftermath
Leaving San Francisco, the Doctor fell victim to a last trap set by the Master, causing yet another case of amnesia. He found himself travelling to different past points in his own timeline, encountering his previous incarnations to regain his memories via telepathic contact with each past incarnation. During these visits, he also offered the past Doctors advice and assistance, even securing the release of Borusa from the Tomb of Rassilon while arranging an inquiry into the trial of his sixth incarnation. At the end of this journey, Rassilon revealed that he had been guiding the Doctor's journeys to make some changes to the pattern of history; the Doctor regained his memories and acquired a new companion, Sam Jones, a young woman from the same Shoreditch neighbourhood in which he lived in during his first incarnation. (PROSE: The Eight Doctors)

Since the Doctor had inadvertently changed his own timeline by travelling through it, (PROSE: Alien Bodies) the "Great Grey Eminence" made a deal with the Faction Paradox to fold the Doctor's timeline back on itself and rewrite Gallifreyan history, at least according to the Book of Lies. The Boy suggested that, as part of the Eminence's plan to re-sterilise Gallifrey, he arranged for the Doctor to travel with Sam rather than someone who would dare to "screw" him. (PROSE: Unnatural History)

As the Eye of Harmony tried to break him down into pure energy, the Master managed to ride the energy into a spare room, which the Doctor's TARDIS then ejected into the Time Vortex to protect the Doctor. The Master, having reconstituted his stolen body, would remain stranded in the Vortex for hundreds of years, rooting through the Doctor's possessions in search of something to help him escape. (AUDIO: The Lifeboat and the Deathboat) Nevertheless, the power of the Eye had re-energised the decaying body he had stolen from Bruce, enabling him to continue to use it. (AUDIO: Day of the Master)

The Master eventually found himself on Kolstan, where he met Artron, and posed as an assistant sent by the Time Lords. When the Eighth Doctor arrived, the Master inflicted a fatal wound on the Doctor and used this to force Artron to operate a machine that would transfer the energy of the native Kolstani into him. However, Artron was able to adjust the machine so that he would absorb the power of the Kolstani instead, although this unintentionally turned them into the Ravenous. When Artron used the power of the Kolstani to disappear with the Doctor, the Master used his future TARDIS to escape to the Time Lord station that all his incarnations used as a base. Meeting with the the "War" Master and Missy, the Master worked with them to stop the Ravenous's alliance and granting the future Decayed Master a new regenerative cycle, allowing him to regenerate into the Reborn Master. The Bruce Master had his mind wiped by his successors and was thrown back into the Time Vortex in order to preserve their timeline. (AUDIO: Day of the Master)