The social science fiction series "Hard to Be a God" is based on the eponymous novel by the Strugatsky brothers, published in the early 1960s. The events take place in the future, on a distant planet called Arkanar. The inhabitants of this kingdom resemble humans, but the level of civilization is akin to the late Middle Ages. Unofficially, the planet is being observed by workers from the Earth's Institute of Experimental History, who have been studying the development of the local society and the path it is taking for several decades. The Earth agents operate undercover.