Gretchen McNeil: 3:59

YOU SHOULDN’T BE HERE.

Josie ignored her inner voice of reason and continued to stare out the passenger window of her car. Parked on the hill above the athletic field, the Teal Monster half-hidden behind a Dumpster, she could just see the boys’ track team running pyramid drills. She remembered those practices well. She’d sit in the bleachers, focused on homework, occasionally glancing up to find the tall, muscular form of her boyfriend sprinting around the all-weather track. Even now, stealing a moment with him from her hiding place in the car was oddly comforting.

That’s so pathetic.

“Shut up,” Josie said out loud.

Awesome, Josie. Talking to yourself while you stalk your ex-boyfriend. Quite a life you’ve carved out for yourself.

A pack of boys in mismatched red-and-white shorts and loose-fitting T-shirts rounded the upper turn. The middle-distance runners were pushing themselves through the last four hundred meters. They ran in a small pack, about eight guys in all, and at that distance they looked two inches tall. The Kaufman twins stuck out like identical sore thumbs, their long, bleached-blond hair flopping with each stride in almost disturbing symmetry. Then Josie’s eyes drifted to the dark-haired runner behind them. Nick.

He ran with a telltale stance—straight up and down with a high kick to the knee. And as the pack cleared the corner, heading down the final straightaway, Nick slipped into an outside lane, whipped around the twins, and pulled ahead. Josie couldn’t see his face but could picture it in her mind. Cool and calm, no display of fatigue or stress. It was his signature finish. While the other runners strained, red-faced, to keep up with him, Nick always had something left in the tank.

As usual, Nick crossed the imaginary finish line several feet ahead of his nearest rival. He threw his arms in the air and jumped around as if he’d just won a gold medal. The other runners dribbled across the line and bent forward, hands on knees, while Nick continued his mock celebration. Then one by one, they all meandered to the inner field for stretches.

Josie sighed and leaned her head back against the headrest. It was almost like old times, if “old times” was just twenty-four hours ago. Nick at practice, Josie watching. She could almost imagine . . .

Josie froze. Below, another figure stepped onto the field: slender, elegant, poised even when picking her way across the spongy surface of the track. Josie could tell right away it was Madison. Her curls rippled in the spring breeze, and before she was halfway to the field, Nick caught sight of her. He stood up slowly, glancing to his right and left as if from embarrassment, and sauntered across the field to meet her.

Madison reached out and grabbed Nick by the waistband of his shorts, pulling her to him. Then right there on the track, she kissed him.

Nick broke off the face sucking after a few seconds, and Josie watched as Madison reached a hand to her neck and lifted something to her lips. She kissed the object before letting it fall back into place. The necklace.

“Fuck you!” Josie shouted. She pounded on the steering wheel with both fists. She hated them both so much. How dare they be so happy? How dare they have done this to her? “Fuck you! Fuck you! Fuck you!” Then she accidentally hit the car horn with her fist.

Madison and Nick instantly looked up toward the Teal Monster’s hiding place. Josie scrunched down in her seat. This was a disaster. How could she have been so stupid? Spying on her ex-boyfriend and ex–best friend. Josie’s blood ran cold. She was going to be the laughingstock of the entire school.

Without sitting up, she turned the ignition over, released the parking brake, and eased her car around the Dumpster. She waited until she was completely out of sight of the track before she sat up in her seat.

She could barely drive home amid the sobs.

3:59 P.M.

JOSIE WOULD HAVE GONE STRAIGHT TO BED THE second she got home, if it weren’t for the explosion.

She was dragging her tired, worn body down the hallway when the foundation of the house rocked as if an earthquake had hit. Josie had to brace herself against the wall to remain upright. At the end of the hall, the basement door flew open, and a bright light flashed through the house, so intense it momentarily blinded her.

It took Josie a few seconds to process what had happened. The flash. The feeling that the house had jumped off of its foundation.

Josie swallowed, her throat suddenly parched, as a creepy-crawly feeling spread across her skin. This had all happened before. In her car, by the side of the train tracks just twenty-four hours ago. Could it be a coincidence? Or something even stranger?

You’re being ridiculous . Josie shook her shoulders, tossing off the inexplicable fear that had overcome her. She didn’t believe in coincidence, or déjà vu, or any of that crap. This was a pattern, and the one thing she’d had instilled in her since childhood by her two scientist parents is that patterns are not random. They always exist for a reason.

Josie set her jaw and marched down the hall.

Time to find the reason.

The basement lab was in a state of chaos. Books and equipment were scattered across the floor, dumped from a metal shelving unit that had tilted over onto the large stainless steel table in the middle of the room. The floor was strewn with broken glass, which crunched under the soles of Josie’s flip-flops, but she hardly noticed. Her eyes were fixed on a piece of equipment in the corner. Mounted on an elaborately rigged series of sawhorses and tables that curved around one corner of the basement, down the full length of the house, and back around the next corner, was a laser.

Not just any laser. Josie recognized the double undulators, compact accelerator, and experimental bending magnets right away. It was a prototype of a compact X-ray free-electron laser—an X-FEL—the multimillion-dollar piece of equipment Penelope had suggested they “borrow” from Josie’s mom for their science-fair entry. And it was sitting in Josie’s basement.

Wouldn’t someone at Fort Meade notice that an X-FEL the size of a minivan and worth more than the crown jewels had suddenly gone missing from a heavily secured government facility? How the hell had it gotten into Josie’s house?

Josie eased her way around an overturned table for a closer look at the laser. She’d never seen this version of an X-FEL before but she’d heard her parents discussing it excitedly over dinner for years. It had been one of the priority projects up at Fort Meade: millions in funding, a team of A-list scientists and engineers, top secret specs no one had ever seen.

Josie bent down and examined one of the undulators. It was one of the most high-tech, cutting-edge pieces of equipment in the world and yet . . .

Something wasn’t right. This rig wasn’t shiny and new and gleaming with custom-made components. It was old, gritty, and looked as if it had been pieced together with odd parts and discarded materials from earlier prototypes. Josie peered at the accelerator tube, her nose so close her breath made foggy little clouds against its metal surface. She could clearly see the seaming where different pieces of the cylinder had been fused together. An X-FEL of that caliber should have had a custom-designed accelerator of all one piece, and this one looked almost homemade.

Josie snapped upright. Homemade? Had her mom built a duplicate version of a top secret laser in their basement ?

“What the hell is going on?”

The words might have come from Josie’s mouth, but they didn’t. She spun around, stumbling over a heavy steel box, and saw her mother standing at the top of the stairs.