"A father and a husband. Which you won't be in prison."

"Prison for what?"

"For theft," she whispered harshly enough that he felt her breath upon his cheek. "Of physical and intellectual property. For making a drug without any license. I can just see you, holed up in some lab like a high school kid making meth, thinking you're not going to get caught." Her mouth wrinkled in disgust.

"It's not as wrong as selling an antidepressant that I know doesn't work to every pediatrician in Mill Valley. And I did that for years."

"That was legal."

"Look," Shane nodded. "We're the only ones who know about it. Me and Prajuk. None of us are tweeting about it. There is no threat to us."

"Until Caleb's girlfriend, who you don't even know, posts it on her Facebook page."

"She doesn't seem like she updates hers very often," he replied with sarcasm.

Janelle stared at him. "It only takes one."

He punched his thigh in frustration, "I asked Dineesh. I asked Anthony. I wrote a request for a grant application. I did everything the right way. They said no. I'm going to help this little girl, Janelle. I am going," he repeated slowly, "to help her."

"Shane," she whispered to herself.

"So I did it myself. And I'm proud of it, actually. Anyway," he exhaled, "we're almost done."

"How can you be almost done? The approvals will take six or seven years." She stared at him. "Oh G.o.d, Shane."

There was nothing to say at this point, he recognized.

"You're not filing this with FDA?"

"This protein has already gone through testing as part of the Airifan trials. It was approved."

"In babies?"

He swallowed.

"Airifan was tested on children with asthma. Not newborns. You could kill her. This baby. You could kill her."

Shane spoke in a lower voice. "If this was Nicky, and we could cure him, you'd be driving me to that lab every night at a hundred miles an hour."

She hesitated then. From upstairs, Nicholas wailed again. Shane seized the opportunity to get off of the staircase. Upstairs, Nicholas was asleep; he'd been having a nightmare. Shane bent over him, stroked his black hair. At what age, he wondered, does the world become so imposing that fear manifests in dreams? He had hoped it would be later than six months.

He returned downstairs to Janelle, who was curled on the couch, crying.

"Bad dream," he explained.

She looked up at him. "Make it better."

2.

All February, Caleb trained in the snow.

The mountains had received enough snow to turn the trails sallow. The expanse of pure white powder came up to his knees, his hips, sometimes his chest. It acted as resistance, like training in water. He welcomed it, choosing paths where he saw no footprints except a mule deer's, or the slithering impression of a milk snake.

Running across the snowpack was risky; danger lay in its blinding white. In the thick roots that hid underneath it like pythons. In the sharp rocks camouflaged in gentle sparkles. In the fearsome cold that could disorient as the beauty of the sunlit snow beckoned him farther and farther away from the roads.

Up in Boulder, people ran their daily five miles equipped with thermal gloves, expensive microfiber jackets, iPhones tucked into specially designed zippered pouches. Caleb disappeared into the backcountry wearing only his light Houdini pants and jacket, plastic goggles, an old fleece hat. In the shade, bitter wind blew shards of ice across his lips. Even under the sun the cold bore its way into his bones. But avoidance of pain was never Caleb's intent. Only avoidance of suffering.

Over the past decade he had successfully extracted any emotional confusion from his life. Jobs, career, family, the expectations of the world, were all like forgotten high school friends. But now, like a patient in remission who with horror senses his symptoms returning, Caleb felt a range of sharp emotions rising up; emotions he thought he had put aside forever.

He ached for June. He ached for her like he had for the heartbreaks of his youth. He ached for her with a desperation that pulled him back from every forward step. He ached for her in a way that affected his posture, his breathing, his heart rate, his clarity of mind upon these icy paths. Even while he slept, he ached. He dreamt of his first months with her, his hours in the fields and the back room at O'Neil's, and awoke in an agony that no strained quadriceps could touch.

Instead of floating in the void, he was constantly thinking of her, where she might be, whom she could be with, and therefore also unbearably conscious of the ripping in his sinews, the lactic acid burning his muscles, the white flame in his lungs, the cold torturing the exposed skin of his face.

And yet he could not stop.

His need was like a living being running beside him, jeering his attempts to return to his previous state. He could smell its funk. He heard its breathing in his room at night, and behind the trees on the trails. No matter how he begged, it would not leave him alone. And so he suffered, day and night, in a way far worse than any cold or ruined ligament.

The only cure for his suffering seemed to be agony. Caleb found that when he pushed his body far past its boundaries, its stress could reach a point where it commanded all of his attention. And freed him. And so even when his subconscious demanded he had to turn back, he kept going, into a place where June and Lily could not reach him, where every step required all of his focus, where agony overwhelmed all thought. At times, lost in the snow and ice pack, he even succeeded in forgetting them for an hour.

He understood Mack's warnings now. Why hadn't he listened? Emotions do destroy the runner's focus. But he had a chance now, to go back to that time before they came, to again run without distraction. He had this opportunity, which June had given him by destroying his heart and leaving him alone. He could seize this opportunity, turn his suffering into anger, use it to train. And possibly survive this.

But still, the more he imagined the baby's soft skin, and June's body against his, and the way their eyes softened to him, the more he welcomed this suffering. It was worth it, he knew, because underneath this pain was promise. The promise that he would see her today. The promise that she might change her mind. And maybe he could not hold her. And maybe he could not tell her that he loved her. And maybe he could not get Lily to Shane. But he could still see them, feel their energy around him through the house. And as long as that promise existed, suffering or not, he felt hope. It was when the pain was gone, he understood, that he'd know his hope was gone too.

The following day, Mack drove him through a driving snowfall to the snow-covered Boulder High School football field. From the back of the Jeep, he jerked a rudimentary red wood sled onto the white ground. A sharp wind rippled across the flat field, shifting the snow in a way that reminded him of icing being spread over a cake.

Mack brushed flakes from his beard and loaded the sled with round black weights. Then he knelt and tied them to the sled with thick twine. Caleb placed the sled's ropes over his shoulders, and Mack tied them in anglers' loops.

"Pick you up later. Pioneer. O pioneer."

Caleb turned, squinted into the icy wind, and began to run hard. He made tight turns through untrampled powder, traversing the field with the weighted sled tied behind him.

At one point, a truck pulled into the lot. Inside were a father and son. They stayed in the cab, staring at him, for a long time. He pulled the sled across the snowy field, trying to ignore them. Finally a dog yelped from their back seat and they drove away.

Caleb returned to the house fevered and blue. The creases around his eyes looked as if they had been deepened with forks. In their room, Kevin was lying on his mattress reading Runner's World. His black hair had been recently buzz cut, and he looked to Caleb like a kid waiting for lights out. Caleb opened their shared closet and found his cold-weather running pants. He sat and pulled them on.

Kevin looked up. "Headed out?"

"Night run."

"You're going kind of hard, man."

Caleb inhaled sharply through his nose, a reflex he'd picked up somewhere in childhood. People at InterFinancial had done scathing impressions of it.

"Nights are where I'm weak."

"Yosemite is still three months away. You've got to slow down." Kevin dropped his voice. "Steve Brzenski died there."

"I don't plan," Caleb said as he pulled on his cold-weather shirt, "on having that experience."

3.

The mouse was four inches from nose to tail.

He had been hand-delivered in a wooden crate, on a Tuesday near the end of February. No one had answered the door at Lab 301, so the courier had called the number he'd been given, and Shane's cell rang in the middle of a team videoconference. He had been hoping to motivate his Southern California reps, who seemed to him to be suffering some kind of overconfidence. He hesitated at the number and ducked out to take the call.

"Can you wait?" he asked the courier.

"Nope, I sure can't."

"Can you leave it there by the door?

"Without a signature, I'll need to send it back."

"Back? It's alive." He could feel the courier's shrug. "Look, wait ten minutes for me?"

Apologetically Shane excused himself, garnering looks from the reps on the monitor, and jogged to the parking lot. It was exceptionally sunny, late February at its San Francis...o...b..ightest, and he had left his sungla.s.ses on his desk. Squinting against the sun he felt vulnerable. He texted Prajuk.

M arrived. What do I do with it?

By the time he signed for his cargo, he had an answer. He unlocked the door and stepped into the cool swath of chemical air. Along the bench, rows of pink petri dishes were now covered in cl.u.s.tered tiny black b.a.l.l.s of bacteria, like BBs. They looked like cancer. He recoiled from them.

Shane opened the crate gently. Beneath some padding he felt a small metal cage. He lifted it out and held it in the air for a moment. Inside stood a mouse. Their eyes met.

Its fur was the yellowed white of a lily. It was neither a cute plump mouse, nor a skinny rodent; rather it was something much more like life. It aroused neither his empathy nor his disgust; no particular emotion at all came to him as he watched its pink pupils.

"Hey, little mouse," Shane said, setting it down.

It walked in circles inside its cage like a dazed soldier.

He followed Prajuk's texted instructions, placed water and pellets of food inside, cleaned out the droppings, placed it on the bench, and shut the shades against the sun. Then he raced back to Helixia. When he reached the conference room, his meeting had ended.

"Sorry," he shrugged to Stacey, who was leaving. "My kid."

That evening Shane skipped the lab and lay on the living room floor, teaching Nicholas to crawl. He loved being eye to eye with him, and breath to breath. His baby's black eyes flickered to the mouse's pink ones, and Shane blinked.Janelle came downstairs, her hands wet from cleaning up a bath, and pondered him.

"Want to get a sitter tomorrow?" She frowned. "Or are you working late?"

This bothered him deeply. Referring to the lab as "working late" implied that he had undertaken some new minor a.s.signment at work, and not the greatest venture of his life. Now that she knew everything, he expected more support. It was not forthcoming.

"Not sure yet," he answered, keeping his eyes on Nicholas's face, which smiled at him with utter love. "My boy," Shane whispered to him, "one day we will take a fishing trip."

Thinking the better of it, he added, "Yeah sure, let's get a sitter."

The following night, he stopped by Lab 301 intending to check in on the mouse. Healy burst upon him, holding an energy bar, grinning crazily.

"Congratulations."

Shane moved into the room, his belly buzzing.

Healy gestured to the cage, his mouth full of dried oats. "He's moving pretty slow. There a wheeze coming from his chest. I can tell you right now his oxygen's abnormal."

"Maybe he's just tired from his trip. I don't think they flew him First."

Healy slipped on a latex glove, opened the cage door, and lifted the mouse by the root of its rubbery tail. The mouse twitched as if touched by spirits.

"I always wondered," Shane asked. "Does that hurt them?"

"If he's hurting, he'll let you know."

Healy carried it over to a metal lab table.

"See if there's any hillbilly music on my laptop," Healy laughed.

"Sorry?"

"Because you're looking at one West Virginian hillbilly mouse."

"They shipped it from Boston."

As Healy took the mouse's measurements, he explained, "This guy is double inbred. His parents are brother and sister. And each set of grandparents are brother and sister too. If he were human, he'd be qualified to work at the DMV."

Shane shook his head.

"The guys at Charles River spliced his grandmother's DNA. They knocked out the gene that makes alpha-one ant.i.trypsin."

"Knocked it out?"

"They added the code sequence to his grandmother's DNA. Shutting down the gene. Knocking it out. Injected that DNA into her embryonic stem cells. There are two copies of every gene, right? So when she had babies, all of them carried one of these reengineered genes, and then one normal one. That only gave her a fifty-percent chance of pa.s.sing the altered gene down, so they bred two of her babies together. These guys' offspring carried two copies of the knocked-out gene. Guaranteeing that this guy has himself one bada.s.s case of alpha-one ant.i.trypsin deficiency. You are the father of an inbred, but alpha-one ant.i.trypsindeficient mouse."