The Doctor and Jo land on a spaceship in the far future as it is attacked by Ogrons, which the human crew see as Draconians. The Doctor and Jo are taken to Earth as spies.
Neither the humans or the Draconians are willing to believe the Doctor and Jo’s story that someone is deliberately attempting to provoke a war between Earth and Draconia.
Accused of being spies, the Doctor is sentenced to imprisonment on the Moon while Jo is taken into the custody of an old enemy.
The Doctor leads a mission to the Ogron home world to apprehend the Master and rescue Jo. But the Master is in league with some old enemies of the Doctor.
On Draconia, the Doctor reveals the Master’s plan to provoke war to the Draconian Emperor. But the Master escapes, taking Jo as hostage.
