Prueba de Fondo (Background Test) explores the daily lives of a group of marathon runners from the Central Highlands of Peru who aim to break more than just their records. Around the practice of athletics in the Andes, many stories of perseverance are woven. One of these is the story of Inés Melchor, a multi-time Pan American champion who, in the past two years, has faced unexpected defeat and the need to rebuild herself.