Serial: ZZZ  Episode Nos. 376, 377, 378, 379, 380, and 381.  Title: Planet of the Spiders

Giant spiders with vast psychic powers have formed a mental link with a group of humans at a meditation center in England.  They seek to form a bridge that will enable them to find the powerful mental crystal from Metebelis 3 that the Doctor took on his previous visit, and the only way that the Doctor can stop them is to conftont his greatest fear...

This story sees the departure of Jon Pertwee as Doctor Who and Richard Franklin as Captain Yates.

starring Jon Pertwee as Doctor Who, Elisabeth Sladen as Sarah Jane Smith, Nicholas Courtney as Brigadier Lethbridge-Stewart, Richard Franklin as Mike Yates, and John Levene as Sergeant Benton. Written by Robert Sloman, Produced and Directed by Barry Letts.

Originally transmitted from 4 May 1974 to 8 June 1974 on BBC1.