But the threat facing America is far more deadly than Communist Russia. The militaristic Tzun Confederacy have made Earth their next target for conquest — and the aliens are already among us.
Two nuclear warheads have been stolen; there are traitors to the human species in the highest ranks of the army; and alien infiltrators have assumed human form. Only one person seems to know what's going on: the army's mysterious scientific advisor, the enigmatic Major Kreer.
On May Day, 1957, the Soviets launch Sputnik I. After it begins its orbit, the signal begins to fade and the satellite is lost. The mission will be erased from history, and when Sputnik II is launched, it will be renamed "Sputnik I."
This is the first published work to feature the Master post-Survival. Later stories would contradict First Frontier, which follows on directly from Survival. The Master is still infected by the Cheetah virus in Housewarming and Prime Time, and is returned to his last crispy incarnation (before Tremas) in Dust Breeding.
The regenerated Master's appearance is based on Basil Rathbone in The Adventures of Robin Hood, according to McIntee, First Frontier's author (DWM 222).
For the purposes of this list, a "regeneration story" is one in which a regeneration is actually and initially depicted. For this reason The War Games is not included below, even though it is commonly thought of as a "regeneration story". It doesn't actually include a clear scene of regeneration, and the preponderance of stories in other media confirm that the Second Doctor did not regenerate at the end of it. Additionally, immediate post-regeneration stories, like the 2005 Children in Need Special — and ones like Castrovalva, where the regeneration sequence was replayed — are not included.
Regeneration is usually considered a biologic process exclusive to Time Lords and a few other species. However, some consider Regeneration and The Eclipse of the Korven to also be "regeneration stories", though neither describes anything close to a biological process. Korven is a particularly hard one to include in this list, because K9 is said to "regenerate" but is largely physically unchanged.