Jane Marple solves the mystery when a local woman is poisoned and a visiting movie star seems to have been the intended victim.
Thomas Becket, Henry II's longtime advisor, finds his friendship with the debauched king corroding when he is unwillingly appointed as Archbishop of Canterbury in an attempt to gain absolute loyalty from the Church.
The TARDIS arrives in London in 1966 and the First Doctor and Dodo visit the Post Office Tower. There they meet Professor Brett, whose revolutionary new computer WOTAN (Will Operating Thought ANalogue) can actually think for itself and is shortly to be linked up to other major computers around the world — a project overseen by civil servant Sir Charles Summer.
