The Cradle Of The Snake
With the Mara once again forcefully asserting its dominance over Tegan’s personality, the Doctor tries to go into his companion’s mind to excise the evil influence once and for all. But the Doctor’s best intentions have even worse results: the Mara takes over his mind instead. The Doctor, under the Mara’s influence, pilots the TARDIS to Manussa, the homeworld of the Mara’s empire… over a century before that empire will come into being. While Tegan is found to be free of the Mara’s influence, the possessed Doctor is working behind the scenes to ensure that the Mara will hold thrall over the entire planet, using Manussa’s mass media as the vehicle for the Mara’s message. Slowly gathering allies and power, the Mara prepares to take over the minds of the Manussans, even if it rewrites history by bringing the Sumaran Empire about too early. In the meantime, Nyssa, Tegan and Turlough watch helplessly as the Doctor becomes an agent of evil, leaving it to them to save Manussa.
written by Stephen Cole
directed by Barnaby Edwards
music by Richard Fox & Lauren YasonCast: Peter Davison (The Doctor), Janet Fielding (Tegan Jovanka), Sarah Sutton (Nyssa), Mark Strickson (Turlough), Dan Stevens (Rick ausGarten), Hugh Fraser (Dr. Hanri Kerrem), Madeleine Potter (Yoanna Rayluss), Vernon Dobtcheff (Dada Desaka), Toby Sawyer (Baalaka)
Timeline: for the Doctor, Tegan and Turlough: between Enlightenment and The King’s Demons; for Nyssa: 50 years after Terminus. This story takes place after The Whispering Forest and before Heroes Of Sontar.
LogBook entry and TheatEar review by Earl Green
His curiosity piqued by the mention of an artifact in the Forge’s vaults bearing the seal of Rassilon, the Doctor discreetly sticks around as UNIT shows up to clean up the Forge’s mess. Hex, still plagued by his doubts that the Doctor ever would have told him the truth about his mother, unwittingly encounters Nobody No One, in a regenerated form, verbally giving the Word Lord the means to take revenge on the Doctor. The Doctor perishes in his attempt to stop Nobody No One from destroying Earth, and Ace and Hex are left to pursue somewhat normal lives. But Hex’s idea of normal isn’t to wind up on an alien world when any mention of space or time travel is considered heresy; he does befriend a fellow time traveler, a woman named Evelyn who claims to have traveled with the Doctor in the past. Ace must learn to accept an even more terrifying fate: married life. Even though he appears to have been beaten by the Doctor, the Word Lord still waits for his chance to strike again, only to discover that the former companions of the Doctor have learned much from their mentor.
The Doctor and Tamsin arrive in a human-built museum on Deimos, the largest of Mars’ two moons, and the site of a frozen enclave of the now-extinct 
After discovering Lucie Miller’s presence, the Doctor hesitates to detonate the charges that would destroy Ice-Warrior-infested 
Laura Rogers (Isabella), Meg Wynn-Owen (old Isabella)
The Demons Of Red Lodge: The Doctor and Nyssa awaken in the dark, surrounded by creatures that almost certainly mean them harm. Even the Doctor has to fight down a panic response to find a way out of the situation, until the time travelers encounter a seemingly friendly face who offers them shelter. They quickly discover the truth: they’re now locked in with something even worse.
Still moving from place to place after leaving their home planet, the Doctor and Susan arrive on the planet Quinnis, a world in the fourth universe. The TARDIS has landed in a market square, and the haggard-looking people of Quinnis seem ready to sell the time travelers anything in exchange for curiosities from their travels – but especially water, as rain has become a rarity. The Doctor quickly grows impatient with the primitive state of scientific knowledge, but is amazed by the local architecture: the town is a vertical maze of unfinished bridges, and the dwellings along its streets are boats, permanently moored to the bridges. Since he’s already performed one miracle – the TARDIS appearing out of thin air – the Doctor is mistaken for a rainmaker, and his protests to the contrary are ignored. The locals want him to make it rain – or else – to trigger their planet’s brief harvest. But even the bountiful vegetation on the ground level could prove to be deadly, especially when the ensuing monsoon washes the TARDIS away.
Determined to make amends for the Christmas that he ruined for her in 2009 – the Christmas that made her decide to leave the TARDIS – the Doctor offers to provide Lucie with a more relaxed Yuletide holiday, taking her to Earth’s future to celebrate with his family for a change. Susan Campbell, still helping to rebuild the Earth and raising her son Alex, is surprised to see the TARDIS show up on schedule. For his part, Alex is still coming to grips with the fact that his mother is an “alien,” and his great-grandfather travels through time and space in a police box. As Lucie dives headfirst into preparations for a perfect Christmas, Susan’s fears about Alex’s future come to the surface: she’s worried that he’ll want to travel with the Doctor instead of staying on Earth to take part in the reconstruction effort. And deep in the TARDIS, something dating back to Susan’s travels with the first Doctor is about to crash the party.