In the Burning Darkness describes a teaching centre for young people who are blind, where a false unity is maintained by a mixture of fear, coercion and diversion where, when persuasion fails, violence is resorted to, and where "education" is seen to play a part in the régime's ideological apparatus and to encourage the acceptance of pleasant and reassuring myths. The play's principal protagonist is Iggy who, although blind like his classmates, is immediately seen to be different from the others because he carries a cane. When Iggy makes a move on Jane, part of the Centre's golden couple with her boyfriend Charles, he begins to challenge and destabilise the values cherished by the Centre.

Buero-Vallejo described In the Burning Darkness as a work "loaded with future", and that observation points the way to why it is being translated now. Although it emerged in 1950 onto a dreary and trivial theatre scene in Francoist Spain, its themes, such as blindness and anxiety of an alienated protagonist, can speak to modern audiences and have a universal, rather than merely parochially Spanish, resonance. It poses a transcendental question about whether or not violence can ever be justified. The teaching centre and the blindness of those within is symbolic of post-Civil War Spain, where anti-democratic abuses were overlooked. The play operates on literal, political and philosophical levels.