Tim Watkins was the senior officer of the team that got the call from the police dispatcher. He and Maynard and Graham had been out to pick up lunch in the truck, and they were within blocks of the address. Watkins had picked up the radio mic and said, “One Zebra Sixty-Three. We’re in the vicinity. We’ll take it.” Bomb Squad teams consisted of two bomb techs and a supervisor, and on this team that was Watkins.

The emergency call had come from David Hills, the owner of the house, who was in France on business. He said he had received a threatening call from a phone in the Los Angeles area. Hills had called the LA police and asked them to check on his house, because the caller had said he was about to blow it up. The suspect had persuaded Hills he was serious: he had the address and described the house—a light gray clapboard one-story traditional Cape Cod with a black front door and white trim, and a Toyota Corolla in the driveway.

The car had clinched it. Hills said he’d rented the car and left it there to make it look as though the house were occupied. That meant this wasn’t somebody who had simply looked online and found a picture of his house. Hills had been competing for a big contract with three eastern European rival companies, and he had been getting vague threats from two of them for over a week before the final call.

Watkins stood on the steps of the house and looked at the black front door. He knew this was going to be the last moment when his feet would stand on anything he trusted. The steps were solid concrete, so they were safe. But he was about to enter another universe alone. For a moment he thought about his wife, Nora; and his daughter, Kelly. The resemblance between the two was uncanny. He could see them in his memory, having dinner last night. He was grateful for the sight but then pushed it away so he could keep his attention on what he was doing.

The other two members of the team were sitting in the truck five hundred feet away, the standard distance. Watkins didn’t let himself envision Maynard and Graham, because he was intent on clearing his mind of distractions and images that competed for his attention. That was also why he didn’t allow any back chatter while he was going downrange on a scene. He reported over the radio built into his bomb suit’s helmet, and they listened.

He knelt on the porch in his olive-drab bomb suit. The Kevlar and steel plates made the suit heavy and stiff, but he managed to get down to eye level with the knob of the front door. The boots were like the rest of the suit. The one part of him that could have no protection was his hands, but he seldom let himself think about that because it made him uneasy. He opened his black canvas tool kit and used the lock pick and tension wrench to line up the pins of the cylinder. Then he tried turning the knob. It offered no resistance. He put away the tools. “I’ve got the door unlocked. Now I’m going to look for reasons not to open it.”

His statement brought another memory, this one the image of Dick Stahl, the retired Explosive Ordnance Disposal expert who had promoted him to the Bomb Squad. That was the sort of thing Stahl used to say. He supposed his subconscious was reminding him to make every move the way Stahl had trained him to. He gave himself a few seconds to clear his mind again.

He stood and squinted into the fisheye peephole set at chest height in the shiny black door, but saw no shadows or lines that might be wires—only a miniature image, like a view through the wrong end of a telescope. He saw a sunny room with a brown leather easy chair under a window with translucent white curtains.

Watkins went down the steps and around the house, looking at the lawn in front of him, selecting the places where he could safely put his thick-booted feet free of trip wires or light beams. If there was a bomb, the mind behind it wasn’t familiar to him. He couldn’t predict or eliminate anything. There could be an electric eye that would set off the initiator if the light beam to its receiver unit was interrupted. There could be a piece of thin wire or transparent fishing line stretched across his path at a level just below the tops of the blades of grass. The trap could be any of a thousand things, or several of them at once, or there could be no trap, and no bomb.

He came to a window that opened onto a dining room furnished with a maple table and chair set. There were two entrances to the room, one a narrow swinging door to the kitchen, like what a restaurant might have, and the other a broad arch that led to the living room. He could see the inner side of the front door of the house from here, and he saw nothing ominous. Once a couple of years ago he had peered in at the inner side of a door and seen a shotgun propped on a coffee table, set up with a wire to fire at the level of a bomb technician’s groin. He had wondered why. He still did.

Watkins considered entering the house by breaking the glass of the dining room window and reaching up to open the latch. But beside the front door he could see the glowing panel of an alarm system. Many alarm systems would trigger at the sound of glass breaking, and a bomb could be connected to the alarm circuit. He took the compact monocular out of his tool kit and focused it on the alarm panel. There was a green light to show that the system had power, but the display said: RDY. Ready. It wasn’t armed. The panel had no visible wires leading from it, but a tie-in could be anywhere in the house, including at the circuit box, which was usually mounted to the interior wall of a closet. But the fact that the alarm was off made Watkins very uneasy. If this Mr. Hill was in Europe and was worried about an extortion scheme, why wasn’t his home alarm system turned on? It didn’t fit. Or had an intruder managed to turn it off?

Watkins paused by the window for a moment and looked again intently at several things he had noticed. The door to the kitchen was one. Any old-fashioned house might have a swinging door to the kitchen, but he couldn’t recall seeing more than a few like this one in his eight-year career. The door itself was a hazard. It was clad in a layer of sheet metal like the ones in restaurants. It was painted white on the upper half, but the lower half was bare metal. That meant it would conduct electricity. Would a bomber ignore that opportunity?

Watkins studied the chandelier above the dining room table. It was a bowl shape with three layers above it dripping with dangling crystal drops that kept the bulb invisible. An antipersonnel bomb with ball bearings or screws inside the glass bowl would disperse at the right level to kill anyone in the room—about six feet.

Watkins took his time. He emptied his mind and stared, trying to notice anything that felt wrong, anything that would inspire a bomber to do something clever. Watkins moved from window to window, following the same procedure. He tried to see what was plugged into each electrical outlet, searching for commercial timers designed to turn lights on and off and make the house seem occupied. Those were about the most reliable timers a bomb could have, and they could deliver 110 volts to a firing circuit.

Watkins looked for shapes he’d seen bombers use before—pipes, of course, pressure cookers, backpacks, satchels, small suitcases. He scanned for pieces of military ordnance that might have been left inside boxes made for them. Artillery boxes were usually simple, made of half-inch by three-inch wooden laths nailed together and painted olive drab with their contents stenciled on them in black. He searched for the shape, not the color, in case somebody had painted one to look harmless, like a toy box.

Watkins knew if an expert had set this house to blow, there would be at least two charges—the big one to destroy the building, and a smaller, subtler one just for someone like him.

When he had stared into the interior through each of the windows, he found himself back at the front steps. He spoke into the helmet radio. “There’s nothing visible from any of the windows. I’m at the front door again.”

He stood on the steps beside the door, reached over, and turned the knob. The spring pressure felt normal, and he heard no clicks. He sighted along the jamb as he opened the door a crack. There were no signs of anything held in place by the door or the hinges about to fall or spring away or sever a contact. There were no wires.

He moved his knife along the bottom of the door to locate the magnet embedded in the door to keep the alarm switch under the threshold from tripping. He found it, then took out his own magnet and placed it against the door in exactly the right spot, so when he pushed the door inward the new magnet would replace the one in the door.

He reached inside and lifted the doormat to check for a pressure pad, and then put the doormat into the doorway to prop the door open. He turned and inspected the alarm keypad on the wall. “I’m in,” he said. “The alarm is off.” A minute later he said, “I don’t see any sign of a device yet. I’m going to look for it.”

Watkins stepped deeper into the living room, inching ahead in his heavy, hot bomb suit. He had to turn the whole upper part of his body to see anything on either side, because the suit’s helmet didn’t have a neck. He used his bright flashlight to focus on one object at a time. He didn’t want to flip any light switches just yet.

He moved the beam of his light around the room to pick up the shine of monofilament fishing line or any thin wires that weren’t meant to be there. Next he turned his light off and searched for thin beams of light from an electric eye in the air.

A glass candy jar filled with multicolored jelly beans drew him to it. The jar was exactly the sort of object a bomb maker would use—harmless looking, transparent, and appealing. He came closer and used his flashlight to search for any hint of an object or a wire hidden among the jelly beans. Maybe it was too obvious for this guy. A professional bomber would know that someone like Watkins would see it as a likely place for the trigger.

The place a bomber wanted the charge was not the first place you’d look. When you looked at the first place, you were still sharp and watchful. The bomber wanted you to work your way to the less likely places. When you got to the least likely place, there it would be. By then you’d be tired and bored, maybe careless enough to open drawers without first checking for contacts, or to step without looking down ahead of your feet.

Watkins refused to rush or get lazy. His mind roamed this nightmare of a house, searching for the other mind, the one that had come here to infuse the building with malice. Watkins had seen bombs go off, and he had seen the aftermath, people simultaneously burned to death and torn apart, charred viscera and brain tissue spilled and limbs wrenched from bodies, blood spattered on pavements and dirt roads. He was aware that in a minute he might experience that destruction. He might already have set off an electronic timer when he opened the front door, and a time-delay relay was about to send the electrical current to the initiator. Maybe now. Or now. Or now.

He went down on his stomach and swept the flashlight beam along the boards of the hardwood floor, trying to spot a single board that was higher or lower than the others. A misfit board could have been lifted and something placed under it.

The floor was perfectly level. Watkins looked up at the ceiling and along the crown molding. He reminded himself that if there was a bomber, he had never seen this person’s work before, and didn’t know his specialties, his quirks, his favorites. He kept looking.

Bombs were not just weapons. They were something more, expressions of the bomber’s thoughts about you, his predictions of your behavior—what you would see, even what you would think and feel. He’d staged a presentation designed to fool you. He didn’t even know your name, but you were the one he was really after. Bombs were acts of murder, but they were also jokes on you, riddles the bomber hoped were too tough for you, chances for you to pick wrong when it was almost impossible to pick right.

Watkins turned his attention to the furniture. First he moved his flashlight along the bottom edges of the furniture and then behind it, and then he moved to the couch. The easiest place to put a charge was in one of the seat cushions. The cushions usually had a zipper in the back or underneath so the cover could be cleaned or the stuffing replaced. One couch cushion could hold a pretty big bomb. Three of them could blow pieces of the house all over the neighborhood.

He touched the front of each cushion with his fingers, palpating it to sense whether there was anything hard, or if the stuffing was too full, or there were any empty spaces. He cautiously pushed the spaces between two cushions apart to detect any wires. He worked his way to lifting them up to be sure they weren’t too heavy.

Next he moved to the big armchairs and repeated the process. After each piece was cleared, he slid it over beside the couch. When he had moved everything to one side, Watkins surveyed the newly bare part of the room to be sure he had missed nothing. He looked at baseboards and molding, sockets, light fixtures, and lamps. He announced, “The living room is clear.” Then he picked up his tool bag and went to the kitchen door.

He took out his mirror and extended its telescoping handle. He slipped it into the thin crack between the swinging door and the jamb, moved it up and down, and rotated it. There was nothing connected to the door. There was nothing on the floor. He adjusted his mirror to reflect the kitchen counters. There were a toaster, a blender, a row of spices, a couple of bottles. One was olive oil.

He saw a small black rectangular box on the kitchen counter. What was that, a phone? A radio? Either could be bad for him. There seemed to be a very thin white cord leading from the countertop to a plug on the wall behind the juicer. He withdrew the mirror, put it away, and picked up the monocular from his tool bag. He leaned into the kitchen, aimed the monocular at the device, and read the brand name. Canon. A camera? No lens, but it looked like camera equipment. As he stared at it, a tiny red indicator on the end came on.

In that silent moment Watkins identified the device on the counter. It was a photographer’s intervalometer, a device often planted in the wild to detect movement of an animal on a trail and trigger a camera many times in succession as the animal passed by.

Watkins half turned his body toward the front door to go back, then realized he was not going to make it. The first electrical impulse would be for a charge near the front door, and the next impulses would race around the house, each one setting off a charge where he might take shelter, tearing the house down over him one explosion at a time. “No,” he thought. “Toward it.”

Watkins pivoted back toward the kitchen, pushed off with his legs and heard the first click of the intervalometer as it sent the first impulse, but there was no explosion. He burst through the swinging door, building speed as he lumbered across the kitchen, dashing for the back door.

The intervalometer’s second click set off an explosion at the front of the house, the one designed to kill him if he’d retreated to the front door. The shock shook him and his ears hurt, as though it had damaged his eardrums. He flung the back door open and launched himself off the back porch to the lawn. He managed to remain on his feet in the heavy bomb suit, still struggling to run.

The second explosion punched out the kitchen windows behind him and showered him with glass, and the third took out the windows over his right shoulder. One after another, the charges blew, the next set at the corners of the house. Watkins kept moving, not able to turn and look back, but he heard a crash he believed was the collapse of the roof over the living room.

The house was being imploded, the way demolition teams imploded skyscrapers and apartment complexes. He knew the only thing that had kept him alive for the past ten seconds was the necessity that the last charge to blow was the one near the intervalometer that set off the charges. The kitchen charge would be the biggest.

In another half second it came, knocking him off his feet onto the grass, clapboards and two-by-fours striking his back. Then clouds of white dust obscured the world.