Joe Newman, a naturalised Briton, is telephoned by his German father, whom he believed long dead, at the same time as a funeral is taking place in Bavaria - with his father's name on the coffin. His investigation in Bavaria reveals startling facts and the obstruction he meets makes him suspect foul play.

When a respectable weaver is wrongfully accused of theft, he becomes a virtual hermit until his own fortune is stolen and an orphaned child is found on his doorstep.

It was noted for being the beginning of the end of the Doctor's exile on Earth, with the Doctor's TARDIS still under the control of the Time Lords (The Mutants) and restricted freedom (The Curse of Peladon and The Time Monster), as well as UNIT and the Master appearing less frequently in compared to the previous two series. As well as the return of the Daleks and the Ice Warriors, this series also introduced Alpha Centauri, Aggedor and the Silurians' aquatic cousins the Sea Devils.

The season is notable for the departure of Sarah Jane Smith in The Hand of Fear and for The Deadly Assassin, a story set entirely on Gallifrey which expounded greatly upon the culture and history of the Time Lords, and the Eye of Harmony and Rassilon are mentioned for the first time. The Deadly Assassin also featured the return of the Decayed Master in a degenerated form and had the Doctor without a companion for an entire story for the first time in the history of Doctor Who. This story is also the first time the limit of regenerations is set.