Jeremy tries to wow Toni with his new job in a music studio, while Mark gets passed over for promotion in favour of Sophie, much to his chagrin.
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.
The Doctor awakes from his coma, befriends some Thals but is captured by the Daleks.
Desperate to prevent the Daleks from releasing their plague, the Doctor, Jo and the Thals infiltrate their base. But the Daleks detect the intruders!
The Doctor and the Thals escape from the Dalek city and the Doctor is delighted to find Jo is alive. But the Daleks are preparing deadly bacteria to kill all life on the planet.