Bruce Willis makes a shocking entrance in 16 Blocks, a thick, juicy steak of a crime-cop-conscience action thriller in the tasty tradition of Prince of the City and a hundred episodes of NYPD Blue. And all he does is walk down a hall. Willis plays Jack Mosley, an NYPD detective gone to seed to rot, really. Jack's got a potbelly, a bad leg, and the ashy pallor of the working drunk he is; in decrepit middle age, he's a clock-in, clock-out lifer whose pickled deadwoodiness is company-wide knowledge. Yet the actor eases us into Jack's rotting universe so skillfully so thoroughly at home with a fat gut, a gray mustache, and a permanent expression of disillusioned sourness, so authentically and without pride-in-prosthetics that at first I thought, jeez, what happened to Willis, for real?
What happened is that old Lethal Weapon precinct vet Richard Donner got together with the erstwhile John McClane of Die Hard, both sank their teeth into a meaty script by relative newcomer Richard Wenk that simmers and boils in real time, and the collaboration has done both director and star a world of good as they freshen up in a well-worn milieu. In 16 Blocks, Jack's rinky-dink assignment on a stifling hot NYC summer morning, grudgingly accepted, is a babysitting chore: He's got to drive Eddie Bunker (Mos Def), a measly, chattering twerp of a petty criminal, the title distance from lockup to courthouse where Eddie is to testify to a grand jury. (A trained New Yorker can make the hike, less than a mile, in 15 minutes, easy.)
Of course, traversing 16 Blocks takes considerably longer. Traffic, Jack's stop at a liquor store, and exquisite bad luck put Eddie in the crosshairs of a would-be assassin, and Jack's split-second cop's instinct to intervene only makes the muck deeper: The backup that arrives includes Jack's old brother in shady blue, homicide detective Frank Nugent (David Morse), and it soon becomes clear that the guys who wanted Eddie dead to prevent his testimony are themselves cops cops as dirty as they come. Is Jack on the side of the force or the punk? (Turning the chewing of gum into a gesture of menace, Morse shows once again how a guy can morph from St. Elsewhere's Dr. Sensitive into one of our most interesting character actors, his pleasant, boyish face now fattened into something much less predictable.)
The race is on. The movie throws in sequences of Donnerian red-blooded action there's some Speed-inspired business involving a city bus, and the production makes use of the proximity of New York's Chinatown to its courthouses for some sharp sequences involving cat-and-mouse chases through atmospheric subterranean kitchens and laundries. But the most exciting moments unfold in stillness, while Jack and Eddie are paused between perils, and Def electric as a punk with a criminal past and dreams of a future as a professional cake baker engages Willis with the seriousness of his patter. Mouthiness from a black man is often used as comic relief in a black-and-white duo, but Def's Eddie is never foolish. And in grateful response, Willis' Jack is never glib.
Besides, the two characters have the luxury of real, reflective time to fill, something so rare in an age of zip-bang-crash-zap action-pic editing as to be classified as ''old-fashioned.'' A helluva lot happens in 16 Blocks an outrageous amount, really, along with a coda that deposits the audience squarely (and I do mean squarely) at a movieland finale. Who knew that looking both ways before crossing is where the real action is?