The Doctor’s urgent mission to trace the origin of the Cybermen’s signal by infiltrating Sector Sixteen

Adric and the Doctor descend into the cavern to disable a bomb meant to irreversibly poison Earth’s atmosphere. The Doctor identifies the release mechanism and urges Adric to withdraw, but …

The Doctor announces the need to depart for Sector Sixteen to trace the bomb's remote signal, aware of the escalating Cyberman threat. His companions push back—teasing exhaustion after a long …