Although this story is about British India, it uses a title associated with Nazi Germany. The Night of the Long Knives was purge that took place in Nazi Germany between June 30 and July 2, 1934, when the Nazi regime carried out a series of political executions, most of those killed being members of the Sturmabteilung (SA), a Nazi paramilitary organization.
The character Hara Singh is loosely based on Hira Singh (1843-1911), ruler of Nabha in northwest India.
This episode takes place in the Thar Desert, India in May 1886 and in Arizona in 1968.