There was an open-air parking garage next to the hotel. I walked into it and hugged the wall, obscured by bushes lining the wall’s exterior.

He appeared a minute after I’d gotten in position. The streetlights illuminated him and cast shadows into the garage where I stood silently by. I watched him stroll past me down the tree-lined walkway in the direction of the Avenida da Amizade, named, like most of Macau ’s thoroughfares, by the Portuguese centuries earlier. The soft drape of his navy sport jacket was too stylish for his surroundings-dress in Macau, I had learned, was almost slacker casual-but I supposed that as a white island in an Asian sea he was going to stand out regardless.

Past the parking garage he turned right into an alley. I glanced back at the hotel exit-all quiet. So far he seemed to be alone, with no countersurveillance to his rear. I moved out to follow him. He reached the Avenida da Amizade and waited for a break in the traffic before crossing. I hung back in the shadows and waited.

On the other side of the street he turned left, looking back over his shoulder, as any pedestrian would, to check for oncoming traffic before crossing. I permitted myself the trace of a smile. His “traffic check” was an unobtrusive bit of countersurveillance. It was nicely done, casual, and I saw from the quality of the move that I was probably going to have a hard time following him solo.

He moved down the wide boulevard in the direction of the Hotel Lisboa, the territory’s biggest casino and best-known trolling ground for prostitutes, and after a moment I crossed the street and trailed after him. The streetlights around us were widely spaced, with ample pools of darkness between them for concealment, and Karate couldn’t have spotted me even had he looked backward to do so.

A few hundred meters farther on, he cut down the steps of an underground passageway. The passageway was H-shaped, its lengths running parallel to the Amizade and its middle running perpendicular beneath it. I moved just a little more quickly to close the gap, and arrived at the entrance in time to see him disappearing into the middle of the tunnel and under the street.

Now I faced a dilemma. If I followed him in and he glanced back, he would make me. If I stayed put and he emerged on the opposite side of the street and hurried on to develop distance, I could easily lose him.

I thought for a moment. Until now, his countersurveillance had been subtle, disguised as ordinary pedestrian behavior. But he was abandoning subtlety now: after all, a pedestrian out for a stroll doesn’t typically cross a street one way and then, a short stretch later, cross back. He knew what he was doing. The question was, which way would he play it? Double back, to catch a follower? Or hurry out the other side, to lose him?

If I had been working with a team, or even just a teammate, there wouldn’t have been a problem. We would have just tag-teamed him in, knowing that if one of us got spotted, the other would fall into place after. But this time I didn’t have that luxury. All I had was instinct and experience, and these were telling me that the tunnel move was a feint, an attempt to draw a follower into the tunnel, weed him out of the crowd, then turn around and catch him. So I moved past the passageway on the right, hiding in the shadows of one of the avenue’s stunted palm trees, hoping I was right.

Fifteen seconds went by. Thirty.

If I had been wrong, this was my last chance to try to cross the street. If I waited until he had emerged, he would see me coming.

Just another second, just another second, c’mon, asshole, where are you…

Boom, there he was, moving up the vertical side of the H, still on my side of the street. I let out a long, quiet breath.

He strolled another hundred meters along the Avenida da Amizade, then cut right. I did the same, in time to see him turn left, down a scooter-choked alley walled in by office buildings to either side. I fell in behind him, window unit air conditioners buzzing like insects in the dark around us.

Three minutes later we arrived at the Lisboa. I followed him in, wondering whether he was hoping to use its many entrances and exits as part of a preplanned surveillance detection route. If so, he’d made a mistake. The Lisboa was too crowded at night; a pursuer could stay close in here without your ever knowing it. Even if he’d had a team positioned for countersurveillance, the nighttime crowds would present insurmountable opportunities for concealment. Maybe he’d designed this route during the day, when the hotel was less crowded? That would have been a mistake, too. Times of day, days of the week, changes of season, changes of temperature-all can make for an environment dramatically different from the one you originally reconnoitered.

I moved in closer and stayed with him, knowing that if he snaked off into the crowded, multilevel hive of the casino I might easily lose him. But he avoided the gaming area, strolling instead in a slow, clockwise loop around the ground floor’s shopping arcade, where clusters of prostitutes from nearby Guangdong province circled like hungry fish in a spherical aquarium. We moved with them, past gamblers flush with fresh winnings, whom the girls eyed with bold invitation, eager to retrieve a few floating scraps from the casino food chain; past middle-aged men from Hong Kong and Taiwan with sagging bodies and febrile eyes, their postures rigid, caught in some grim purgatory between sexual urgency and commercial calculation; past security guards, inured to the charms of the girls’ bare legs and bold décolletage and interested only in keeping them moving, circling, forever swimming through the murk of the endless Lisboa night.

Karate left the building through a secondary exit. I still wasn’t sure what he had hoped to accomplish by going inside. The shopping arcade, like the hotel itself, was too crowded for meaningful surveillance detection. Maybe he had planned this part of the route poorly, as I had initially speculated. Or maybe he had simply been window-shopping in anticipation of indulging himself later that night. Not impossible: even professionals occasionally slip, or pause to fulfill some human need.

His subsequent behavior supported the “indulgence” hypothesis: after the Lisboa, I didn’t spot him doing anything further to check his back. He must have satisfied himself with the provocative tunnel stunt. It wasn’t an ineffective move, actually, and probably would have been enough to flush someone else. Hell, it would have flushed me, if my instincts had been a little less sharp or if I hadn’t done my three weeks of homework.

He continued northwest on the Avenida Henrique. The street was straight, dark, and heavily trafficked, and I was able to follow him from far back. My eyes roved constantly, searching the hot spots, the places I would have set up countersurveillance or an ambush. Nothing set off my radar.

At Senado Square, the area’s main pedestrian shopping commons, he turned right. The square would be crowded, even at this evening hour, and I increased my pace to ensure that I wouldn’t lose him. There he was, moving up the undulating lines of black and white tile, to the left of the illuminated vertical jets of the square’s central fountain, along the low, pastel-colored porticos of the Portuguese-style storefronts, incongruous amid the surrounding Asian sounds and scents. I followed from about ten meters back. Hong Kong pop blared urgently from a storefront. The smells of roasted pork and sticky rice wafted on the air. Thick groups of shoppers drifted back and forth around us, chatting, laughing, enjoying the comfortable closeness of the arcade and the carefree camaraderie of the evening.

We moved off Senado and onto quieter streets. Karate browsed among the street stalls-fruit, lingerie, traditional Thai costumes at three for a Hong Kong dollar-but bought nothing. He seemed to be heading in the direction of St. Paul’s, the site of a once-splendid Portuguese church, over the centuries gutted again and again by fire, and standing now only as a sad façade, a haunted relic, illuminated at night like a bleached skeleton propped at the apex of a long series of steep stairs, where it broods in ruined majesty over the city that has grown like weeds around it.