Buenos Aires, March 1982. On the streets of the Argentinean capital, people are challenging the military dictatorship. The walls of the school are thick and redoubtable. A secure promise of the guaranteed preservation of the good old days of school routine from anything that may happen outside its walls in the neighbouring streets, in Buenos Aires itself, in the Argentina of 1982. María Teresa is a classroom assistant at that school, an innocent - or maybe just ignorant - mistress of ceremonies, a bystander. She is twenty years old. She started work when it was still summer and Mr. Biasutto, the chief classroom assistant, made quite clear to her at her first interview the sort of attitude she is expected to adopt with students because it would not be an easy task to arrive at what he called 'the optimum surveillance point': Always on the 'qui vive', never missing a thing, but never giving cause for alarm amongst the students. A surveillance which would pick up on everything but would ...