Mark is up for promotion at work, but loses out to Sophie.
Injured by the Orgrons, the Doctor asks the Time Lords to send the TARDIS after the Daleks. Leaving him to sleep and recuperate, Jo goes to explore the planet Spirodon.
Desperate to prevent the Daleks from releasing their plague, the Doctor, Jo and the Thals infiltrate their base. But the Daleks detect the intruders!
A force of ten thousand Daleks is coming to life below the surface of Spiridon. The Doctor and the Thals must find a way to defeat the Daleks before they invade the galaxy.
The Doctor awakes from his coma, befriends some Thals but is captured by the Daleks.