They were a popular team, Mackay and Kearns, and they both spent a lot of extra hours raising funds for the families of police officers killed or injured in action.

This morning, in the jostling hub of the airport’s Terminal C, they were on high alert for anything that looked even remotely suspicious. Normally they patrolled slowly, moving from one end of the terminal to the other but never straying too far from the sightline of the security staff.

This morning it was more difficult, owing to the sheer volume of passengers. The shouts of the airline staff rose above the throng-This way, sir… I’m sorry, sir-right to the end of that queue right there… We’re moving it along, sir, just as fast as we can… just keep moving along… keep moving right along.

“Jesus, Pete,” said Danny. “I was in Greece one time, and they treated herds of fucking billygoats better’n this.”

Pete Mackay laughed, like always at Danny’s humor. But then the innate Boston cop on terrorist alert took over. “Yeah, but this is serious. We couldn’t hardly move if anything happened. I been trying to calculate, maybe a full half-minute from here to get to the security guys-unless we knock down a coupla dozen passengers.”

“You mean like Ryman against the Steelers last month-that time he took three defensive linemen with him-hell! That was some play.”

“I guess that’s the kind of thing-a head-down rush. But seriously, these are tough operating conditions, and we have to stay in view of the passengers and staff.”

“Sure as hell be better if we could move a coupla feet without crashing into someone.”

The two police officers tried to move along toward the head of the queue, but turned back. “Just don’t want to get out of sight of security, that’s all,” said Mackay.

Donald Martin was the junior vice president of a Boston brokerage house, and he was doing his level best to clear the new passport control system and get on a flight to Atlanta. He had no baggage and expected to be back home in Newton, west of Boston, by midnight.

He was traveling with the president of his corporation, a silver-haired financier, a Boston Brahmin named Elliott Gardner, thirty years his senior. Donald was quietly reading the Globe; his boss was staring somewhat aimlessly into the distance, bored sideways by the airport procedures, unamused that their first-class tickets did not allow them to bypass this unattractive closeness to the rank and file. Particularly as the queue had come to a tiresome halt.

Behind them stood one passenger, apparently alone, and behind him was a family, two very young children presumably with mom and dad. They had a lot of baggage piled on a cart. One child was screaming. Elliott Gardner hoped to god that the family was not traveling first-class on Delta to Atlanta.

“WA-HAAAAAH!” wailed the child. “Jesus Christ,” muttered Elliott Gardner. And then he felt a mild tap on the shoulder. The passenger behind him was making contact. He turned around and came face-to-face with a youngish man, well dressed, no more than thirty, of decidedly Middle Eastern appearance. He could have been Turkish or Arabian, but not Jewish or even Israeli. This was a face born and bred in desert or casbah.

The man smiled broadly. “Excuse me, sir,” he said. “I have two quite heavy briefcases here, and I’m just going over there to Starbucks for some coffee. Would you mind keeping an eye on one of them for me-kick it along if the queue moves?”

Elliott glanced down at the brown leather briefcase on the floor. A well-mannered man, unaccustomed to rudeness, he replied, “No problem. Leave it right there.”

Donald Martin absent-mindedly looked up from his newspaper and asked, “What did he want?”

“Oh, just to watch his briefcase while he went for coffee-he’s over there, heading for Starbucks. Guess I should have had him get some for us, since the goddamned queue has stalled.”

“Where is he?” said Martin, suddenly alert.

“Just over there at the Starbucks counter.”

“What’s he wearing?”

“Some kind of tan-colored jacket, I guess.”

Martin swung around and pointed, “You mean him, that guy moving down the hallway, against the crowd?”

“Yeah, dark hair, that’s him. What’s up, Don?”

“Well, he just walked straight past Starbucks, for a start.”

“Probably going to take a leak,” replied Elliott.

“Well, he just broke every rule in the book, about leaving luggage unattended. And so did you. You have no idea what’s in that briefcase. AND the guy looks like a fucking Arab.”

Elliott Gardner looked startled at this apparent brush with a dangerous corner of the outside world. And his very junior vice president threw his right arm in the air and looked straight across the crowd to the patrolling Pete Mackay and Danny Kearns.

“OFFICER!” he yelled, loudly. Very loudly. “RIGHT HERE-OVER HERE, PLEASE!”

Officer Mackay spun around. He could see Don Martin’s raised arm, and he dodged and ducked thirty yards through the crowd. Danny Kearns was right behind him.

When they arrived, Donald Martin was herding people back, away from the briefcase, which now stood in solitude like a couple of roosters in a cockfight, hemmed in by the spectators.

“Officer,” said Martin, “a guy who looked like some kind of an Arab left that case right there and said he was going to Starbucks for coffee. But he didn’t. He went right past Starbucks, and he’s on his way out of the building right down that corridor.”

Pete Mackay grabbed a small state-of-the-art stethoscope from his belt and stuck one end into each ear, the long tube onto the briefcase. “Jesus Christ!” he breathed. “Danny, there’s a slight ticking sound. Get the detector.”

Danny Kearns pulled a wire contraption from his belt and held it against the case. It immediately bleeped. “That’s metal inside, Pete, and possibly explosive. This is a fucking live one.”

“What’s he wearing?” yelled Pete. “What the hell’s he wearing?”

“Tan-colored jacket,” replied Elliott Gardner. “Black T-shirt. He’s not tall, short black hair. Looks obviously Arabian.”

“GO GET HIM, PETE! LET ME TAKE CARE OF THIS.”

Danny Kearns had patrolled for a lot of hours in Boston’s airport. And he knew the real estate. Out through the wide glass doors, there was a four-lane throughway for dropoffs, cars, limos, and buses. Officer Kearns was accustomed to making split-second decisions, but had not previously been confronted by anything quite so urgent. Whether to evacuate the terminal as fast as possible? Or to take the death-or-glory route, grab the briefcase and get it out of here, hoping to Christ the sonofabitch didn’t blow?

The latter course held another diabolical question-what to do with the damn thing once it was outside? The terminal on the departures level was surrounded by concrete parking lots, and Danny Kearns sure as hell didn’t want to be holding the goddamned time bomb for longer than necessary.

His mind raced. If he flung the briefcase into the concrete ramparts of the parking garage, he’d wreck a few cars and maybe knock down a couple of floors, maybe injure or even kill a dozen people. If he left it in the terminal while he ordered people out, it would surely kill a thousand.

No contest. Danny Kearns, Patriots fan, husband of the beautiful Louise, father of Mikey and Ray, grabbed the briefcase. He held it in the classic grip of the running back, tucked against his body, his right hand securing its underside. Instincts, honed from watching thousands of hours of NFL football, caused him to run with a slightly lower gait than normal.

He looked ahead at the glass doors, and he set off, legs pumping, running hard for the first objective, brushing aside passengers, hitting anyone in the way with a crunching shoulder charge. Ahead of him was a group of maybe six people blocking the doors-the goddamned defensive secondary, too many of ’em. Danny rammed into the first astounded air passenger, then spun away, coming back in, hard on the left, grimly hanging on to the briefcase.