We find in this novel the passion of Arturo Pérez-Reverte for art and good, because in a well-crafted thriller, fast-paced, it immerses us in the very closed world of graffiti and coded. And what surprises! First the plot briskly! We follow the footsteps of Lex, an art historian unconventional, launched on the trail of a charismatic street artist aggressive nickname, Sniper, and whose head is a price for a billionaire who is accused of being responsible for death of his son 17 years old. Lex will foil the ambush hit men who are on the Snipper track, but also face the graffiti artists, marginalized youth launched the night to attack the cities to mark their poetic or aggressive graffiti. The outcome of this hunt will be sudden and unexpected Pérez-Reverte Then we discover an unknown and fascinating universe, that graffiti artists. As graffiti on the walls of cities are usually associated with vandalism and an eyesore, Arturo Pérez-Reverte, who followed at his risk and peril those young graffiti artists and agile in their nocturnal expeditions, present them as rebels, anarchists and misfits whose ephemeral graffiti trying to raise awareness and are "antisocial shots that hit in full cord." Finally, we are invited to reflect on art, its function today, its appropriation by greedy art dealers, making it a subject of speculation and the author's charge against contemporary art is violent. And if the graffiti background, in its ephemeral and free aspect was "the only living art" today? ... Here is a question that will perhaps change the way we look on the walls of our cities? ...