An elderly lady approaches the front desk at the Twelfth Precinct in Copacabana and demands to speak with the chief. Tired after a long day, she leaves without further explanation, promising to return. Two hours later, Dona Laureta is dead, and witnesses' accounts vary as to whether she was pushed or fell in front of the bus that killed her on one of the busiest avenues in the city. Veteran police chief inspector Espinosa quickly pinpoints a suspect in Hugo Breno, an unassuming bank teller whose solitary existence takes on a sinister cast as he shadows the inspector's movements across the city. Meanwhile Espinosa discovers an unsettling connection from the past between himself and Breno, and must turn his trademark psychological inquiry inward to determine how murky memories of a murder from long ago might play into Dona Laureta's untimely passing.