While doing some research, Sarah happens on a report about the death of a "John Smith", who acted as a science adviser to the government. He died in an explosion while examining an alien object. This happened on the Isle of Wight on 5 July 1950.
Sarah is devastated to learn that the Doctor will die. For the next several weeks, she and the Doctor continue their time travels. Whenever they land, she is terrified until she learns that the landing is not the Isle of Wight.
One day, however, they do land on the Isle of Wight. The Doctor has noticed Sarah's preoccupation, but she tries to shrug it off. They arrive at the site where an alien object was found, and the Doctor talks his way past a Major Williams. When they get closer, they notice a man approach the object, which then explodes, killing the man.
They later learn that the man's name was John Smith. He was a refugee that came to Great Britain after World War II. When Sarah explains what has been on her mind, the Doctor tells her he wouldn't just approach an unknown object without some caution.
Sarah teases the Doctor about his choice of alias, and the Doctor responds with "And you're a fine one to talk — Miss Smith!"
- Sarah and the Doctor visit a human colony, where the Doctor solves a murder, and the African plains.
- Sarah discovers what she thinks is the Doctor's death while exploring information about Sir Charles Grover's Whitehall projects.
- The Doctor compares his time travel to changing lines on the London Underground.
- The Doctor offers to take Sarah to Aldeberan.
to be added