One of the biggest investigations in medical history began when a mysterious killer disease broke out during independence celebrations in Philadelphia in 1976: Legionnaire's Disease. NOVA traces the search for a cause and cure - a search bedeviled by false trails, accusations of incompetence and cover-up, and increasing urgency as the death toll mounted.

The TARDIS lands on the jungle planet Deva Loka, where an Earth expedition has been sent to study the Kinda, a tribe of primitive people. Three team members have already vanished. Are the Kinda as primitive as they seem?