An approaching spaceship is detected by UNIT and lands in England.  UNIT meets the crew of the spacecraft who appear to be gold skinned humanoids calling themselves Axons.  They claim that their ship is damaged and they need to repair it.  They will give Axonite, a substance that will end food shortages, in exchange.  It turns out that the Axons are actually all a part of a parasitic entity called by the Master in order to drain the Earth's energy.

The Doctor is eventually able to lock the Axons in a time loop.  When the Doctor returns to Earth he tells the Brigadier that the Master also escaped.