Serpent's Tongue

"Serpent's Tongue" is the eighth episode in the eighth season of Doctor Who, set on the distant planet of Manr. It sees the first appearance of the Mara since 1983's Snakedance, and also the first appearance of the White Guardian masquerading as the Guardian of Mara since 1983's Enlightenment. It is considered the first in a three part story arc re-introducing the White Guardian, along with Phoenixfire and The Omens.

Synopsis
The Doctor and his companions crash land on the planet of Manr, where they encounter the reborn spirit of the Mara, which recognises the Doctor and possesses Isabella. Can the Doctor defeat the Mara again? Or will he loose his companion? And who is the sinister Guardian of Mara that appears so familiar to the Doctor?

Continuation and references

 * Like with Tegan in both Kinda and Snakedance, the Mara possesses the Doctor's female companion.
 * The White Guardian refers to "wrong boats in wrong times" (Enlightenment), "a fellow kin now no more, but maybe she still exists" (The Ribos Operation, referring to Romana) and "the stone that tried to break you" (The Stones of Blood), all of which the Doctor takes some time to understand and recall.
 * The Mara speaks through Isabella as it did Tegan, attempting to torture the Doctor with its knowledge of the Time War.