The escalating battle between the Doctor and the Cybermen over control of Earth's temporal space and the planet's conversion to a Cyberman stronghold

Commander Lytton, betraying his Dalek past, bargains his crew's conversion for the Cybermen's favor as leverage for survival. Unveiling his alien origins from Vita Fifteen and knowledge of the Cybermen's …

The Doctor spots Cybermen closing in on Russell and Peri as the policeman breaks free from handcuffs, escalating the immediate danger. Without hesitation, he abandons covert observation and physically seizes …