Ralph Watson

The wife of one of Kersey's friends goes missing after an evening class and later her tutor is found murdered. Meanwhile, Kersey's relationship with Lane threatens to lead him into deep waters.

The Doctor visits the planet Peladon fifty years after his last visit. Whilst there he discovers that several miners have died and that the ghost of Aggedor is apparently to blame.

Chancellor Ortron accuses the Doctor and Sarah of being in league with the rebel miners and sentences them to be punished by Aggedor himself.

Desperate to avoid a revolt from the miners, the Doctor attempts to expose the fraud of Aggedor's ghost. Alpha Centauri has summoned Federation troops, but whose side are they on?

The Ice Warriors have taken control of Peladon. Pretending to cooperate, the Doctor concocts a plan to defeat the invaders.