UNIT investigates when scientists go missing kidnapped by an alien trapped in the 13th Century.
The Doctor discovers that the alien is a Sontaran warrior called Linx who is trying to repair his spaceship.
Linx is providing advanced weaponry to Irongron and his men who prepare to attack Sir Edward’s castle.
The Doctor races to save the captured scientists and to prevent the course of history being changed.
The Doctor and Sarah return to present day London but are mystified when they find the city deserted.
The Doctor plans to capture a dinosaur so that he can discover who is transporting them through time.
The Doctor has captured a Tyrannosaurus Rex but the conspirators don't intend for it to remain captive for long.
Sarah awakens to discover that she is on a spaceship that left Earth months ago and is heading for a new world.
Sarah discovers that the spaceship passengers are all victims of a deception.
Dinosaurs are appearing all over London in a last effort to frighten people away.
The TARDIS suffers a power drain and is forced down on the planet Exxilon.
The Daleks weaponry is rendered useless by the power drain and they are forced to make a truce.
The Daleks force the Exillons to work as slave labour to mine the life saving parrinium.
The Doctor and Bellal arrive at the centre of the Exxilon city but the Daleks are preparing to depart.
The Doctor makes a return visit to Peladon some years after his previous visit.
Chancellor Ortron accuses the Doctor and Sarah of being in league with the rebel miners.
Desperate to avoid a revolt from the miners, the Doctor attempts to expose the fraud of Aggedor's ghost.
The Ice Warriors have taken control of Peladon. Pretending to cooperate, the Doctor concocts a plan.
Commander Azaxyr and his Ice Warriors are revealed as traitors, in league with Galaxy 5.
The Doctor and the miners take the upper hand in the fight to reclaim Peladon from the Ice Warriors.
Mike Yates contacts Sarah-Jane about mysterious goings on in a Buddhist retreat in the English countryside.
A highly intelligent spider from Metebelis 3 arrives on Earth in search of the powerful crystal.
Following Lupton, Sarah is transported to Metebelis 3 where she is captured by the human villagers.
With the Doctor in a coma, his only hope of survival lies with a device inside the TARDIS.
Sarah makes a bargain with the Queen Spider and returns to Earth with the Doctor in the TARDIS.
The Doctor's past has caught up with him, and now he must risk death to save the universe from the Great One.