Doctor Who: The Newbies Guide
The Green Death
This is the fifth and final story in Season 10.
The Third Doctor has white hair, a large nose, and tends to dress as a society dandy. He has a love of technology, historical name-dropping, and vehicles. In The War Games the Doctor's people (the Time Lords) sentenced him to exile on Earth. In Spearhead from Space, he was appointed as scientific advisor to UNIT. In The Three Doctors the Time Lords revoked his exile.
Josephine "Jo" Grant is the Doctor's assistant at UNIT. She failed General Science A Level, but has had training in escapology, cryptology, and explosives. She first appeared in Terror of the Autons..
Brigadier Lethbridge-Stewart is the commanding officer of the United Nations Intelligence Taskforce (UNIT). He worked with the Second Doctor to defeat threats to Earth on two occasions (in The Web of Fear and The Invasion. In Spearhead from Space, he teamed up with the Third Doctor to prevent an invasion by the Nestene and the Autons. During that story he persuaded the Doctor to work as his scientific adviser.
Sergeant Benton is a UNIT officer. He worked with the Second Doctor to prevent a Cyberman invasion in The Invasion. He has been working with the Third Doctor for several years.
Captain Mike Yates is an officer in UNIT. He has worked with the Doctor for several years.
Recurring and Historical Characters
The United Nations Intelligence Taskforce (UNIT) is an organisation devoted to protecting Earth from extra-terrestrial threats, In The Invasion, the second Doctor teamed up with them to prevent an invasion by the Cybermen. In Spearhead from Space, the third Doctor became their scientific advisor.