The story is about the relationship established between Martin Mondragon, a young psychologist (Sbaraglia) and the man who seeks to collect a debt left by his grandfather a long time ago.
José Sagasti (Lito Cruz), Satan's agent, presents himself to Mondragon as the one in charge of collecting the old debt and informing the guarantor of his fate.
But soon after their first meeting, Sagasti starts playing mind games and making Mondragon's life a living hell.
Through its eight chapters, this mini-series recounts the struggle of Martin to avoid surrendering his soul to Sagasti, the envoy of the devil.
Both characters give life to a confrontation that is waged on the earthly plane, and at the same time the one-upmanship also plays on the psychologies of both men.