"Set in Los Angeles in the slight future, ... Theodore, a complex, soulful man ... makes his living writing touching personal letters for other people. Heartbroken after the end of a long relationship, he becomes intrigued with a new, advanced operating system, which promises to be an intuitive and unique entity in its own right. Upon initiating it, he is delighted to meet "Samantha", a bright, female voice ... who is insightful, sensitive and surprisingly...

The Tardis arrives in London in 1966, where the Doctor and Dodo visit the recently opened Post Office Tower. There, they discover a brilliant new problem-solving super computer called the Will Operating Thought ANalogue. But when WOTAN decides that it should rule the world, the Doctor is the only person who can stop its rampaging War Machines from destroying London.