Bruno Cadogan has flown from New York to Buenos Aires in search of the elusive and legendary Julio Martel, a tango singer whose voice has never been recorded yet is said to be so beautiful it is almost supernatural. Bruno is increasingly drawn to the mystery of Martel and his strange and evocative performances in a series of apparently arbitrary sites around the city. As Bruno tries to find Martel, he begins to untangle the story of the singer's life, and to believe that Martel's increasingly rare performances map a dark labyrinth of the city's past.