Leave it to a veteran thriller writer to go where few, if any, novelists have gone before -- the unexplored hallways of the Department of Homeland Security. This wild goose chase of a novel follows a retired, disgruntled Secret Service agent called back into duty by the DHS to investigate an arsonist's connection to a possible Inauguration Day terrorist attack. Like any good page-turner, the addictively enthralling story twists and turns from there. Granted, Deutermann's cat-and-mouse shtick borders on the excessively elaborate and occasionally strays into the predictable, but ''Firefly'' certainly has its effulgent moments (wait till you get to the jaw-dropping ending!).