Maurice Colbourne

Cybermen capture the Doctor and Peri and bring them to Telos, where they plan to use the TARDIS to invade Earth. With Colin Baker.

The Doctor's former enemy Lytton doesn't make it clear where his loyalties lie and the Doctor is captured by the Cybermen.

Davros is held captive within a prison in space and the Daleks come up with a rescue plan; the Doctor, Tegan and Turlough are trapped.

After a prison space station holding Davros is attacked, the Doctor, Tegan, and Turlough find themselves trapped in a time corridor that forces them to Earth, where they discover that a sinister plot is afoot.

The battle at the prison station continues.

The Dalek agents on Earth take extreme measures to protect the time corridor.