When the Doctor's old foe, the Master, comes back from the dead, the Doctor tries everything he can to stop him, but later finds out the Master is still dying, because the Master's wife, Lucy Saxon, had interrupted his revival, and, the Master is helpless from death, but, using an immortality gate, he transplants himself into everyone living in Equestria, with Gallifrey returning.

Rated Teen for violence, suspense, mild language, death, and everything related to the Master
A/N: This is John Simm's master, along with a version of the Doctor that regenerates into my version of the Doctor