On the morning after the Venice Preservation Society’s annual black-tie gala, art restorer and legendary spy Gabriel Allon enters his favorite coffee bar on the island of Murano to find General Cesare Ferrari, the commander of the Art Squad, eagerly awaiting his arrival. The Carabinieri have made a startling discovery in the Amalfi villa of a murdered South African shipping tycoon—a secret vault containing an empty frame and stretcher matching the dimensions of the world’s most valuable missing painting. General Ferrari asks Gabriel to quietly track down the artwork before the trail goes cold.

The painting in question is The Concert by Johannes Vermeer, one of thirteen works of art stolen from Boston’s Isabella Stewart Gardner Museum in 1990. With the help of a most unlikely ally, a beautiful Danish computer hacker and professional thief, Gabriel soon discovers that the painting has changed hands as part of an illicit billion-dollar business deal involving a man code-named the Collector, an energy executive with close ties to the highest levels of Russian power.

The missing masterpiece is the lynchpin of a conspiracy that if successful, could plunge the world into a conflict of apocalyptic proportions. To foil the plot, Gabriel must carry out a daring heist of his own, with millions of lives hanging in the balance.