The Doctor is perturbed when a spate of deaths follows the break-up of an alien mass in
the atmosphere. But this merely the latest incident in a conspiracy that threatens the entire planet, and the
Doctor himself is embroiled in the plans of all the players.
The Brigadier's concern is heightened by the possibility of traitors at the vey heart of UNIT. Leaving for Geneva
to discover the truth, he little realises the deadly motives of an enemy agent on his own doorstep. The Doctor and
Liz, meanwhile, discover that London doesn't have a monopoly on alien invasions.
What are the gargoyle-like creatures that kill without mercy? What do they want from our planet- and how do they figure
in top-secret governmental plans?
As the lines between allies and enemies begins to blur, the Doctor finds himself fighting to save the Earth once again.
But who will he be saving it for?
Featuring the Third Doctor, Liz Shaw and UNIT, this adventure takes place between the TV stories
INFERNO and TERROR OF THE AUTONS.