John Rain is back. Which means somebody is about to die.

Barry Eisler's Asian-American assassin, dubbed "the best cool killer" in some thirty years by the San Francisco Chronicle (well, since The Eiger Sanction, with its killer portrayed by Clint Eastwood on the silver screen), returns for his third adventure. This one finds Rain living quietly in Brazil in a carefully crafted identity he hopes will let him leave his past behind him. But despite his attention to every detail, his hidden romantic streak won't allow him to leave well enough alone: he finds he must visit Naomi, a woman from his past, a woman for whom he harbors "feelings" which are dangerous to a man in his profession. He thinks he's secure enough, that he's waited long enough, that the trail has gone cold and his identity is secure. But he's wrong.

The result: willingly or not, Naomi reveals his whereabouts. Shortly thereafter, Rain receives a visit from a freelancer for the "Christians in Action" (i.e., the CIA), with a lucrative offer for another of his patented "kills" that looks like the result of natural causes. Rain isn't particularly inclined to work for the CIA, largely because he doesn't like working for large organizations (as he puts it at one point in the early going, the right hand often doesn't know what the left hand is doing - in retrospect, an effective bit of foreshadowing).

An old contact with the CIA wants to take out a ruthless and shadowy arms dealer who supplies weapons to various criminal groups worldwide. Since the dealer spends a fair amount of time in Macau's glitzy casinos, and given Rain's ability to operate unnoticed in Asia (the result of his Asian-American heritage), they think Rain is the perfect man for the job - as long as the fellow dies a "natural death." Since his Brazilian cover has been blown, he can no longer trust Naomi, and he has a need to replenish his financial reserves, Rain reluctantly agrees.

He ends up in a posh Macau hotel, a rented Japanese prostitute on his arm for cover, waiting for Belghazi, the arms dealer, to show up. Things start to go sour almost immediately, however, as Rain recognizes the presence of another operative loitering in the hotel as well. He shadows the guy and tries to take him down for information, but in the resulting conflict is forced to kill the man with his bare hands (Rain is an exceptionally proficient student of the martial arts).

When Belghazi does show up, Rain recognizes additional layers of danger: Belghazi is an exceptionally aware target, a dangerous man in his own right. And the trophy blonde on his arm seems remarkably aware of her surroundings as well, which signals to Rain that he will have to be at the top of his game. As his efforts play out against the glitz of Macau's casinos and the dark realities of its grimy underbelly, he ends up in an uneasy "alliance" with the blonde, an unknown operative named Delilah with an agenda all her own. And he also learns that his fears about the CIA were not unfounded: there may well be some folks in high places who don't want Belghazi taken out at all, and they are playing their own games with Rain's life.