Bill watched Tom clambering around inside the cage like a monkey, snipping and twisting together bits of wire with flawless accuracy. As he concentrated, he stuck his tongue out of his mouth, just as he used to when he made clay soldiers or drew pictures of flowers for his mother.

As the day’s end approached the kids seemed to have finished their cage. It was a box that was taller than Tom. Anna made them stand back, threw a few switches, and watched. Nothing happened as far as Bill could see save for a dull humming, a sharp scent of ozone. But Anna nodded, as if satisfied.

Then the kids broke away and, as if going off duty, wandered off around the lab.

Some of them went to the bowls of food Bill and Wayne had put out around the room. They seemed to avoid the dishes Wayne had slyly dipped his fat fingers into. Others, Tom and Anna among them, began playing. They started to throw Tom’s electronic Heart around, catching it like a football, kicking it along the ground like a soccer ball. That was okay. The Heart was built for kids and was meant to last a lifetime, and was more than strong enough to take the punishment. The kids were noisy now, calling and yapping and even tussling a little.

As if they were normal.

Bill studied the wire cage, wondering how safe the damn thing was. At the end of each day the inspectors and experts crawled over everything the kids did. If it wasn’t self-evidently safe they would shut it down and pull it apart, or maybe amend it to remove the hazard. The next day the kids would just start putting it back the way it was, unless physically restrained from doing so. And so it would go on, like building that bridge in Apocalypse Now, a battle of stubbornness between the kids and their adult keepers, until the kids were forced — or sometimes chose — to move on to something else…

That was when it happened.

Bill saw that the Heart had rolled between Wayne’s feet. The kids were standing in a loose pack in front of Wayne, watching him.

The moment stretched, growing tauter.

Then Wayne looked at the Heart, and the waiting kids. Something like a grin spread over his face, and he lifted his hefty foot and pushed the Heart back along the floor.

A little boy called Petey, no older than Tom, collected the Heart. Petey, shyly, put the Heart back on the ground and rolled it back to Wayne.

Again Wayne returned it.

Back and forth the Heart went, a couple more times. The kids came a little closer to Wayne.

Then Petey picked up the Heart, and threw it at Wayne.

Wayne caught it one-handed, grinned wider, and threw it back to another kid.

Who threw it back again.

The game gradually built up steam. The kids seemed to be warming to this surprising new Wayne, this big bear of a man who was suddenly prepared to play ball with them. They ran around, starting to laugh and call, and threw the Heart to each other and to Wayne. Even Anna — Tom’s quiet, reserved, honorary sister — was joining in, her thin frame rising like a giraffe’s above the rest of the children.

Bill started to relax. If Wayne was playing with the kids, however unimaginatively, at least he wasn’t doing them any harm.

Bill kept watching, however.

Now Wayne got hold of the Heart, wrapped it in his huge fist, and lifted it high above his head.

The kids crowded around him, calling. “Me! Give it to me!” “No, me!” “Me, me! Give it to me! My turn!” Bill saw that Tom was at the front of the little crowd, jumping up and down right in front of Wayne, reaching for the Heart.

Wayne looked over the kids, one by one, still grinning, as if selecting. And Bill saw the change in his face, the hardening of his fist around the solid plastic toy.

To Bill it was a nightmare of paralysis. He knew he could never reach Wayne in time.

In slo-mo, down came Wayne’s arm, that heavy plastic ball nestled in his fist, the Heart heading straight for Tom’s big, fragile skull.

There was a blur of motion. That big arm was knocked sideways, with something clinging to it.

Wayne’s meaty forearm brushed Tom, knocking him back, and the boy screamed; but Bill knew in the first instant that he wasn’t badly hurt. The other children scattered away, yelling.

Wayne stood up, roaring, his face twisted, lifting his arm high above his head. The girl, Anna, had sunk her teeth deep into the flesh of his muscle. And now she was hanging on by her teeth, her arms and legs dangling, bodily lifted off the ground by Wayne’s brute strength.

Bill grabbed Tom and pulled him away.

Wayne shook once, twice; Anna’s head was rattled back and forth, but still she wouldn’t let go. So Wayne took a pace and slammed his arm against the wall. Bill heard a crack as Anna’s skull collided with the smooth plastic there. She came loose of his biceps. She seemed stunned, her limbs loose, and she slid to the floor like a crumpled doll. Her mouth was bloody, like some carnivore’s.

Wayne clutched his torn flesh, blood seeping through his fingers, snarling obscenities. Bill saw something white there, embedded in the flesh — one of Anna’s teeth, perhaps.

Bill tensed. One leap and he would be on Wayne’s back.

… And then something came ghosting through the wall. It was a glowing, fizzing bullet: just a point of light, yellow-white, bright as the sun, and it cast shadows as it moved.

Bill, shocked, skidded to a halt.

The light slid smoothly through the air, floating like Tinker-bell, heading downward and toward the center of the room.

Wayne, looming over Anna, didn’t see it coming.

The light slid neatly into the top of his head. There was a sharp smell of singed hair, burned meat. Wayne convulsed, eyes flickering. The light passed out at the nape of Wayne’s neck, following an undeviating straight line, as if the man, two hundred pounds of vindictive muscle, were no more substantial than a mass of mist and shadows.

Wayne, shuddering, toppled backward like a felled tree.

The children were wailing. Bill found Tom clutching his legs; he reached down, lifted up his son, and buried his face in the crying boy’s neck. “It’s all right. It’s all right—”

“What the hell—”

Bill turned. Principal Reeve and a couple of the other assistants had come in at a run. “Get the medic,” Bill said.

“What happened?”

He pointed to Anna. “She’s hurt. And her teeth—”

But Reeve was no longer listening to him, it seemed, despite the blood and fallen bodies.

At the center of the room, something was glowing, yellow-bright. Bill turned. It was the yellow dot, the glowing Tinkerbell. It had come to rest at the heart of the children’s wire cage; it bobbed to and fro, following complex paths.

The children were calmer now. A couple of them were with Anna, trying to help her sit up. But the rest had started to cluster around the cage and its imprisoned light point; its brilliance shone over their faces.

Bill followed them, his son still in his arms. Fascinated, Bill reached out a hand toward the cage. He felt something, a ripple, as if a mild electric shock were passing through his system. He reached farther—

A hand grabbed his arm, pulling it back. Tom’s hand.

Maura Della:

Bill Tybee was pretty distressed, and he had a right to be, Maura

thought.

Wayne Dupree had, it turned out, come from an extremist Christian group who believed the Blue children were the spawn of Satan, or some such, and so required destruction. He had gotten himself into the center on a fake resume and references from other members of his cult group: credentials that, Maura agreed, the most minimally competent vetting process should have weeded out.

On the other hand, Dupree hadn’t succeeded — and not because of the system or the presence of other adults, even a devoted parent like Bill, but because of the freakish plunging of the Tinkerbell anomaly into his body, just at the right moment.