Jon Pertwee bows out as the third incarnation of the TimeLord in this popular sci-fi adventure series. The blue crystal that the Doctor took from Metebelis III in a previous adventure is desperately sought by the Eight Legs, a race of mutated spiders, as the final element in their plan for universal domination. With help from an old mentor, the Doctor realises the only way to foil the plot is to make the ultimate sacrifice. The Doctor must risk death to return to the cave of the Great One and save the universe…
The Doctor receives a mysterious package from his old companion, Jo
Grant. Sarah joins Mike Yates to investigate sinister events at a
Buddhist meditation centre.
Lupton, now under the control of a giant spider, infiltrates UNIT HQ
and steals the Metebelis crystal. But the Doctor is unwilling to give it
up so easily and a chase begins.
Following Lupton, Sarah is transported to Metebelis 3 where she is
captured by the human villagers. The Doctor uses the TARDIS to follow
Sarah, but the spiders are waiting.
With the Doctor in a coma, his only hope of survival lies with a device
inside the TARDIS. Sarah is captured by the spiders and is held
prisoner in their larder.
Sarah makes a bargain with the Queen Spider and returns to Earth
with the Doctor in the TARDIS. There they meet K’anpo, the Doctor’s
Time Lord guru who has the Metebelis crystal.
The Doctor takes the blue crystal and returns to Metebelis 3 where he
must face the spider ruler, the Great One. But it is an encounter that
he may not survive.