1. The Sound of Silence

The Doctor arrives in the village of Linnet, Lancashire to find it eerily silent. He soon discovers that the locals, with the exception of the barmaid Alison Cheney, are terrified of strange creatures that live underground.

2. Meet the Monsters

The Doctor strikes a blow against the Shalka. However, the aliens capture the TARDIS, forcing him to call in UNIT for assistance.

3. Trouble on the Move

After capturing Alison, the Shalka force the Doctor to give them access to the TARDIS.

4. Sound of the Underground

Having survived being thrown into the black hole, the Doctor examines a captured Shalka. The aliens take control of all of the evacuees from Lannet, including Alison and Joe.

6. Hitting the Right Note

After the Shalka unleash their plan to destroy Earth's atmosphere, the Doctor and Alison must find a way to defeat them and save humanity.