Arson investigator Kerry Murphy has a unique talent for sniffing out the cause of fires like the one that killed her mother years ago. She also has a secret, known only to the mysterious stranger named Silver, a ''consultant'' who needs her cooperation in stopping the psychopath who burned his brother alive and who's holding national security hostage to his own demented ego. Silver has an uncanny gift for getting under Kerry's skin, which is both the good and bad news--good because it doubles their chances of finding the man behind the terrifying weapon of the title, and bad because Kerry can't afford to be vulnerable to Silver or any other man. Johansen has written a taut thriller that's not quite as combustible as its title but one that will keep readers fired up enough to stick with it to the last page. --Jane Adams