The future is dying. All over the universe, gaps are beginning to appear. From the space lanes terrorised by the rag-tag remnants of the once-mighty Rocket Men, to the empire of the Gorlans, stricken by a terrible civil war. Gaps in space/time, portents of the end of everything.
Only three beings might prevent it. The Doctor, a renegade Time Lord from Gallifrey. The Master, another renegade Time Lord from Gallifrey. And another Master, yet another renegade Time Lord from Gallifrey.
One Doctor. Two Masters. What could possibly go wrong?