Therefore, its known narrative elements are not a part of the Doctor Who universe as we, on this Wiki, choose to define it. It may have been the basis for a similar story in another medium, however — and that story may indeed be valid.
The Inheritors of Time was a planned American stage play by John Ostrander developed and nearly performed in the mid-1980s. Written by Ostrander from 1982 to 1984 with advice from Terrance Dicks and John Nathan-Turner to ensure it didn't interfere with the show's storyline, the script was approved by the BBC upon completion. The play was announced at the 1984 Chicago Tardis 21 convention with a full cast reading where Patrick Troughton played the Doctor. A year later, a preview of the play was performed at the same convention using actual planned cast members. The play was nearly completely organized with a set budget of $500,000 and an initial run in Park Ridge, Illinois starting 12 May 1986, with plans to tour the States afterwards, but less than two months before this time monetary backers pulled out of the project and made it impossible to continue. (DWM 341)
The story of The Inheritors of Time was set thousands of years after the Doctor's death. A plague nearly eradicates the Time Lords, leading to the Tribunal wanting to make humanity into a new race of Time Lords. However, they find that Earth has disappeared. The Tribunal have preserved the Doctor's body for such an occasion and they revive it using "the half-life left from the enforced regeneration in The War Games", regenerating it into a Fourteenth Doctor played by American actor Roger Mueller. After reclaiming his TARDIS from a Museum of the Bizarre, this Doctor goes to three key points human history to Earth's timeline. (DWM 341) The concept of a "half-life" leftover from the Second Doctor's regeneration would later feature in the fanfilm Devious.