Vietnamese gangsters have come to Brattleboro, Vermont, and they're playing havoc with the bucolic town, which usually has the luxury of much more limited crime waves. Restauranteur Thomas Lee's family is terrorized by a well-organized break-in; none- too-bright Benny Travers, who'd hoped to capitalize on a gang war to strengthen his homegrown gang, is drugged, smothered, shot, and driven off a cliff; and one of the gangs, stung by recent reversals, decides to get back some of its own by the swift, sure route of killing a cop. Lt. Joe Gunther is quick to trace the warfare back to a street killing in San Francisco, but even he's surprised by the way the stain of violence widens to take in a wholesale operation to smuggle illegal immigrants over the Canadian border. Wangling himself an appointment as deputy US marshal, Gunther takes advantage of his new federal powers to harry the rival ringleaders, powerful Da Wang and upstart Truong Van Loc, upstate and over the border, but can't prevent a series of pyrotechnical showdowns between waves of Asian gangsters and equally numberless lawmen ranging from the state police to the FBI to the Mounties. Mayor's sixth book (Fruits of the Poisonous Tree, 1994, etc.) is in every way his biggest, though the outsized scale works against the intimacy of Gunther's earlier cases, keeping you from getting very close to any of the players before they get plugged and planted and the dragnet moves on.