Daley, whose last novel (The Fast One, 1978) was a sorry detour into carracing, is pretty much back on solid home ground again--with a gory story of cops and crooks in N.Y.'s Chinatown that rips along through the first half, then bogs down in predictable chases and showdowns. The cop-hero is Capt. Artie Powers, 46, an abrasive guy whose individualism has kept him from becoming a precinct commander. Now, however, there's headline violence in Chinatown--a restaurant massacre which Powers happens to witness (he pursues the killers, gets hero-treatment)--so he's cynically handed the Chinatown precinct . . . ""to take the heat off the mayor."" And Powers finds that crime control in C'town is nearly a joke: the Mayor has declared the gambling dens off-limits (""it's not criminal, it's cultural""); youth gangs terrorize merchants, none of whom will testify; and, above all, NYPD policy is to pooh-pooh existence of a ""Chinese Mafia."" But Powers is convinced that this Mafia exists and that its godfather is prosperous mortician Jimmy Koy, a former Hong Kong cop and devoted family man who controls the gangs, who's building a drug empire, and who now (thanks to that restaurant massacre) has become unofficial ""Mayor of Chinatown."" So Koy is soon being wiretapped (with help from some retired missionary nuns who speak Koy's rare dialect); he's also being trailed by Chinese undercover cop Luang, who wins the confidence of a recent teen-gang recruit (he tearfully confesses to a gang execution). But all this evidence promptly collapses--the teenager is murdered--and, in the book's weaker second half, a desperate Powers follows Koy to Hong Kong, where the godfather is tightening up his heroin network. Also following: TV news-star Carol, with whom happily married Powers has been having a hot but guilty affair. Much chatter with Hong Kong officials ensues; Powers and Carol are nearly killed by Koy's cop-thugs; and all finally return to N.Y.--where Powers closes in on the arriving drug shipment and has a psycho-showdown with Koy (whose ultimate downfall involves his secret bigamy and utter loss of ""face""). Unfortunately, the pace in this second half is sluggish, with far too many narco-suspense clichÃ‰s. And Powers' angst over Carol and disillusionment (""Koy had murdered the old Arthur Powers"") is unconvincing. But the Chinatown/police detail is tart and gritty, the gang-violence is riveting, and--though overlong and a little disappointing--this should prove popular with those who enjoyed such other Daley books-in-blue as To Kill a Cop, Target Blue, and Prince of the City.