'THE DOCTOR'S BREATHING SEEMS TO HAVE STOPPED. THERE IS NO PULSE OR HEARTBEAT, AND HIS SKIN IS ICY COLD.'
Alone with the injured and unconscious Doctor, Jo Grant ventures on to the planet Spiridon to find help.
But in the lush undergrowth of Spiridon there lurks disease, poisonous plants, invisible enemies and, most sinister of all, an army of Daleks, waiting in secret for the signal to mobilize - and conquer.