Diana was halfway through her run up Brackett Hill when this idea came to her, drawing her attention away from thighs that screamed at her to stop. She pulled out her ear buds and let them bounce against her chest, the music too faint to hear.

She and Tom used to run this route together. When she’d complain about the incline, he’d tease her and promise a back rub when they reached home. Since his death eighteen months ago, she had directed her runs here rarely, only when she was interested in torturing herself.

To distract her thoughts from her aching shins, she puffed up her chest to get more air in her lungs and started to make a list of all of the reasons Why Widowhood Wasn’t the Worst Thing. She imagined writing the list on the Notes app on her phone, the place where she tracked what she needed at the grocery store. Instead of apples, milk, cheddar cheese, and juice boxes for the kids’ lunches, she wrote:

Diana reached the top of the hill, where the street ended in a grove of beech trees. This neighborhood was the much-desired part of town, the section where shingle-covered, gable-roofed mansions from the late 1880s clustered with modern teardowns built by biotech money. The higher on Brackett Hill, the better the view, and those with the most money settled at the very top amid towering trees. On a clear day, Mount Wachusett could be seen in the distance, and the lights of Boston, though only a short drive away, seemed to hover on the edge of existence, someplace else entirely.

Concerned about losing momentum and giving in to her instinct to start walking, Diana turned left onto Donahue Road, pumping her legs as she moved. On another day she might have spun around to take in the view, the expensive one that Brackett Hill residents didn’t have to share with anyone else. But today that view would be hidden, a winter haze shrouding her hometown.

Donahue, thankfully, was level here, and Diana was able to catch her breath, throwing her arms above her head, hoping to rid herself of the growing stitch in her side. Running faster now, she continued to make her list: No one to disagree with me. Well, the kids did that, so she erased it and tried again.

I can keep the heat as high as I want.

She had started making lists as a kid. Why My Bedtime Should Be Later had been pitched to her father at age seven; he had laughed and given her fifteen more minutes. That was when she saw the power of the list and began to use it frequently.

Why I Am the Better Daughter had been presented to her parents in the tenth grade after her sister Andrea was caught sneaking out to meet a boy. Her parents had been amused by that one; her sister, not so much.

In college, she used the list to choose her major (Why I Should Study Sociology Instead of History), decide which parties to go to on weekends (Why Phi Tau’s Mixer Will Be Better Than Sig Ep’s), and choose which shoes to buy (Why I Should Get the Doc Martens Instead of the Fluevogs). Her use of lists had waned after graduation, and it was only now, at forty-three, as she adjusted to life without Tom, that they had reappeared.

There’s no one to help Phoebe with her math homework.

Diana stopped, bent over, gasping. The breath in her chest was violent and sharp. This is so hard, she thought.

Moments passed before she could stand up. Hands on her hips, she looked around the quiet street. A car pulled through the wrought-iron fence at the Hobarts’ house, heading toward her. Jon had been Tom’s law partner; Lisa had once been her close friend. Unwilling to engage in mindless small talk, Diana turned around, straightening her Red Sox cap and tucking a strand of limp, sweaty brown hair behind her ear. She put her ear buds back in and started running, her gaze straight ahead.

Three miles later, Diana turned onto her street, where the trees were just as old as those on Brackett Hill, but the houses—colonials built in the 1920s—were smaller and closer together. The Beastie Boys’ “No Sleep Till Brooklyn” faded out as she finally slowed to a walk and turned up her driveway, past her car, which desperately needed to be washed.

As she climbed her front steps, she waved to her next-door neighbor, Ramesh. He waved back as he took his briefcase from the back seat of his mini-van. His daughter, Mira, had invited Phoebe, Diana’s eight-year-old, for a playdate. The girls were inseparable, and their impromptu get-together had opened up a slot for Diana to go on her run, exercise being one of the first things to drop from her to-do-list when Tom was diagnosed.

She opened the front door, and a gust of winter air followed her inside. She took off her sneakers and vest, dropping both on the bench next to her son’s basketball gear in the cluttered front hallway. She found Duncan in the kitchen, sitting at the island, eating an apple, clad in workout pants and one of Tom’s shirts, a They Might Be Giants concert tee. It was too big for him and had a tear at the neck, but Diana washed it dutifully whenever she found it in the laundry basket, imagining a college-aged Tom wearing the shirt while dancing in the aisles of a darkened theater. She poured herself a glass of water and sat down on the floor to stretch.

“How was practice?”

Duncan didn’t glance up from The Golden Compass. He had read it first with Tom when he was nine. She wondered what had prompted him to reread it now, but he had only shrugged when she asked.

She waited, leaning down to grab her ankles and stretch out her hamstrings. “Duncan, put down the book and talk to me,” she asked, more patiently than she felt. “How was practice?”

He finished off his apple, tossing the core across the room into the sink. “Coach made us run extra laps because we were goofing off. That was a pain.” He stuck the paperback under his arm and pushed away from the island, making his way to the sink. He picked up the apple core and dropped it in the compost bin. “How was your run?”

“I need a new mix to listen to.”

“I’ll put something together for you. How about some Drake? Or Kanye?” He grabbed the laptop from the counter, where it sat on top of the pile of mail, unpaid bills mixing with newspapers that needed to be recycled and notices from the kids’ school that were probably important. Before, the computer had been Tom’s, but now she and Duncan shared it, with Phoebe occasionally practicing math drills on it while Diana made dinner. Diana kept the computer in the kitchen, instead of across the house in what had been Tom’s office. She needed everyone to be close by now, in the same room.

“Did either of them release music in the 1980s?”

“No, but—”

“1980s only, buddy. I need songs from a time when my biggest worry was when my braces were coming off.”

“Your call, but you’re missing out.” Duncan turned back to the screen, grinning. The blue light from the computer buzzed around his face. He looked more and more like Tom each day: dark blue eyes, sandy blond hair, freckles across his nose. Diana wondered if he saw his father when he looked in the mirror. “If you let me put in some current music, you’d see a big improvement over Duran Duran and Tears for Fears. You should think about it.”

“You know what you should think about?” Diana asked, standing up and turning her arms in circles, trying to shake off the remaining tension from her run. “A shower. And homework. You can work on the playlist later.”

Duncan opened his mouth to respond, but Diana spoke first. “I have to get into the shower, too, and there’s lots to do before bedtime.”

He closed the laptop and turned to leave the room, but stopped at the threshold, came back, and swiftly kissed Diana on her cheek.

She reached for a hug, but he was gone, thundering up the stairs. When he was little, Duncan would never leave a room without kissing or hugging her. That had stopped for a while when he turned ten, much to Diana’s regret. But when Tom died, everything had changed. Now Duncan, at twelve, was always aware of where she was in the house, often touching her, as if to make sure she was still there.

She grabbed her phone and texted Mira’s mother, Lakshmi, to send Phoebe home. Upstairs the shower turned on, the pipes rattling as the water heated.

A moment later the front door opened, and Phoebe’s rapid footsteps banged into the kitchen. “Lakshmi sent home food for us. I left it at the front door.”

“Hi—”

“Did you find the time capsule?”

Phoebe stood on her tippy-toes, her face hopeful, her beloved Bear Bear in her arms. She and Duncan had been pestering Diana to locate the Leap Day Time Capsule they had assembled four years ago. Diana barely remembered it, but Duncan’s memory was clear: they were supposed to open it today, Leap Day, February 29, 2016. Diana had looked everywhere—dressers, cabinets, boxes in the attic, even the bathroom linen closet—but without success.

“Not yet, honey.”

“But today’s Leap Day, Mama. We have to open it today.” Phoebe’s face crumpled, tears threatening.

Diana crouched down to meet her eyes. “Phebs, it’ll turn up. Maybe not today, but we’ll find it.” She kissed her forehead. “Let’s go upstairs. You and Bear Bear can sit on the window seat and read while I get ready.”

Mollified, Phoebe made her way to the steps, trailing Bear Bear behind her, his blue, furry bottom bouncing on the treads. Diana went to get Lakshmi’s dish, stumbling over Phoebe’s boots and coat lying across the floor. Her daughter had also left the front door wide open.

“In February. In New England,” Diana said, shaking her head. She tidied up and carried the bowl into the kitchen, peeking inside. Macaroni and cheese from scratch, Phoebe’s favorite. Lakshmi had made food for them every week for months now; it was her way of looking out for them. Diana slid the bowl into the refrigerator and followed her daughter upstairs.

An hour later, nearly 7 PM, Diana stood in front of the open refrigerator, shivering. She closed the zipper of her sweatshirt, stopping it right under her chin. Her hair, still wet from her shower, dripped down her back. She had hoped to cook for her children tonight but had lost track of time. She took Lakshmi’s dish from the bottom shelf and slid it into the barely warm oven, wondering if she had anything to pair with it.

“Mama, how do you spell leaf?” Phoebe called from the worn wooden table where she was practicing her spelling words. Duncan sat next to her, immersed in writing an essay on Ancient Greece.

“There’s a dictionary in the office, on the shelf next to the desk. See if you can find the word on your own.” Diana continued to search in the refrigerator. She pushed aside the milk—still good, amazingly—and found her mother’s fruit salad. A bag of baby carrots in the back of the crisper would work too.

“But, Mama, can’t you just tell me?” Phoebe’s voice started to vibrate up toward a full-fledged whine.

“We’re not doing that tonight, Phebs. Go look.”

Phoebe frowned but got up from the table. She walked through the kitchen, grabbing a carrot as she went and crunching on it as she skipped away.

“Duncan, mac and cheese okay with you?”

His chattiness from earlier had been replaced by silence.

“Duncan?”

The mood swings of adolescence surprised her: one moment he was affectionate and responsible, the next grumpy and non-responsive, communicating only in grunts or eye rolls. The teenage years are going to be long, she thought.

“Mama! Look what I found!” Phoebe ran back into the room, hopping from one foot to the other, practically dancing. In her hand she waved a large manila envelope. On the front, written in bright red marker, was Time Capsule: Do not open until February 29, 2016. “Is this the time capsule? The one you couldn’t find?”

“Where was it?”

Duncan was next to her now. “That’s it! I remember. Good job, Phebs,” he said, suddenly participating and speaking in complete sentences.

Phoebe beamed. “It was behind the dictionary. Stuck against the back of the bookshelf. Can we open it, Mama? Now?”

“So strange. I thought I looked there.” Diana took the time capsule from Phoebe and turned it over in her hands. It looked so benign, so innocuous, and yet something about it unsettled her. The hair on her forearms rose up, and she shivered again, although she wasn’t sure if it was because of her wet head or something else.

She hadn’t wanted to find the time capsule, she realized. In the months since Tom had died, she hadn’t let herself think about the past, their good times together. The time capsule made looking back unavoidable. Her breath grew shallower, and everything around her blurred. Her focus on the time capsule tightened, as if she were looking at it through a telescope. She closed her eyes and tried to steady herself, breathing in and out.

“Mom?” Duncan asked. “Don’t you want to see what’s inside?”

Diana opened her eyes and put her arm around him. She forced a smile. “Of course. Let’s go to the table so we can spread out.” She handed it back to Phoebe. “Lead the way, honey.”

Once they sat down, Phoebe looked from her brother to her mother, demanding their attention. “Ready?” She arched an eyebrow, a trait she had inherited from Susan, Diana’s mother, and in a flash Diana saw an adult Phoebe before her, time jumping ahead too quickly.

“Go ahead,” Diana said, wishing she felt ready.

Phoebe flipped over the time capsule. It was unsealed, closed only by a silver clasp, the wings holding the flap in place. Carefully and slowly Phoebe urged up one side of the clasp and started on the other. She hunched over, her tongue sticking out and her feet swinging. Diana felt an urge to speed up the process—to grab the time capsule and rip it open herself—but so much of parenting was prioritizing her children’s needs, letting their best interests overtake her own. After a few moments the second side of the clasp was opened and Phoebe looked up, triumphant. She turned the time capsule upside down, and the contents fell onto the table.

Duncan bent down to pick up something that had landed on the floor. “Look, Phebs, this is a picture you made.”

They each held a corner of the paper as they examined the crayon drawing.

“You can tell I was really little when I made this,” Phoebe said critically. “I’m a much better artist now.” She handed the paper to Diana and turned her attention to the pile in front of her.

Looking at the drawing kickstarted the muscle that pulled memories from where they were stored in Diana’s brain, hidden at the very back, under all the loss, sadness, and loneliness. Out of shape and abandoned by disuse, the muscle creaked and stretched as it searched about, trying to locate the night they had assembled the time capsule, four years earlier. The night was there but fragmented, like pieces missing from a puzzle.

Duncan had come home from school with the assignment, adamant that they all help put it together that night. No waiting for the weekend when they had more time; he wanted them to put together the time capsule on Leap Day.

So there they had been, gathered together on a Wednesday after dinner, working on Duncan’s homework. Diana had sat with Phoebe, handing her crayons as she colored a picture of a family of kittens. At Phoebe’s direction, Diana had labeled each one, the names written in thick lines of pink: Mommy, Daddy, Duncan, me.

Tom had made it home early that night, the first time in weeks. Still dressed in his good gray suit from court, his tie askew and the sleeves of his blue oxford shirt rolled up to the elbows, he had looked tired, with hollows under his eyes like half-moons and his shoulders folded up tight, the stress from the day not yet released. Diana remembered reaching over to rub his back, feeling the knots in his spine below her hands. Slowly Tom had relaxed into her and smiled.

Soon after that Phoebe had started yawning, making Diana realize that they had missed bedtime. Duncan and Tom had agreed to finish assembling the time capsule while she put Phoebe to bed. On their way upstairs, Tom had ruffled Phoebe’s hair, kissing both her and Bear Bear, his hand tight on Diana’s waist, as if telling her to come back soon. Then he had leaned back and opened a beer, the crack and fizz of the can finishing off her memory like an exclamation point.

She didn’t remember the rest of the night.

Turning her attention back to her children, Diana pushed the drawing aside. “What else do we have?”

“Here’s some of my math homework,” Duncan said, holding up a worksheet with a red smiley face on top. “I made some stupid mistakes when I was younger.”

“Everybody makes mistakes, Duncan,” Diana said absently. She scanned the front of the Boston Globe from four years earlier; stories about the presidential race and winter snow dominated the headlines. Not that different from today.

They passed items back and forth. A photo of the four of them apple-picking was there, along with Duncan’s school portrait, a picture of Phoebe in her nursery-school classroom, and the ticket stubs from Duncan’s first Celtics game.

“Here’s the interview I did with Dad.” Duncan held up a paper stained with something brown. Tacos, thought Diana suddenly. They had eaten tacos for dinner that night.

“Read it,” Phoebe said.

“Go ahead, Duncan,” Diana urged, the ominous feeling rising inside her again.

Duncan cleared his throat and began to read. “Name: Tom Morgan. Age: 47. Address: 90 Newton Road, Alcott, Massachusetts. Occupation: Attorney. Hobbies: Playing basketball with Duncan. Hopes for the future: I’d like my son to remember to pick up his Legos.” Duncan’s smile grew wistful as he read, and then he bit his lip.

Diana tried hard not to cry.

“Daddy was funny,” Phoebe said.

Diana leaned over to kiss her head. “He was. He was also right about your brother’s inability to pick up his Legos.”

Phoebe giggled.

“Seriously, this is not an issue anymore,” Duncan said.

“Your room is very messy,” Phoebe said.

“Mine is messy? Have you ever cleaned your closet, Phebs? I think there’s something living in there.”

“Enough,” Diana said. “Is that it for the interview? Or is there more?”

Duncan turned back to the paper in front of him. “Favorite Book: Pinkalicious.”

“That’s my favorite,” said Phoebe.

“Yeah, we all know that. Dad liked it a lot too.”

“Of course he did. It’s a very good book.” She kissed Bear Bear. “I miss him.”

“Me too,” Diana said softly. “You want us to stop? Is this too hard?”

“We have to keep going,” Duncan said. “You’re okay, right, Phoebe? Don’t you want to see more of this? More of Dad?”

Phoebe nodded, her arms tight around Bear Bear.

Duncan continued, “Favorite Vacation: Going to the Cape with my family. Favorite Season: Winter.”

“Daddy liked winter because he liked to go sledding down that big hill by the library. I like that too.”

“Me too, Phebs,” said Duncan. “We like a lot of the same things as Dad.” He returned to the interview. “Advice to Yourself in Four Years: Get outside and eat more vegetables. Hero: My wife, who makes every day together better.”

“Did he really say that?” asked Diana.

“It’s kind of cheesy, but that’s what he said. Here you go, Mom.” Duncan handed her the paper.

There on the taco-stained page was the interview, in Duncan’s shaky eight-year-old handwriting, misspellings and all, with Tom’s sweet message.

“This is also for you.” Duncan pushed a white envelope across the table. Diana’s name was written on the front. She recognized Tom’s handwriting.

“What is it?” Phoebe asked.

“I think it’s a letter from your Dad.” Diana traced her name with her ring finger.

“Open it,” Phoebe urged.

“I’m not sure.” Diana’s breath grew shallow, and the shiver from earlier returned, her body trembling.

“Please, Mom,” Duncan whispered.

Diana looked up to meet his red-rimmed eyes, and before she could change her mind she inserted her finger in the corner of the envelope and ripped, the sound of the tearing filling her ears. She reached into the jagged opening and pulled out two sheets of white paper filled with Tom’s handwriting, large and curving. Smoothing the pages out on the table, she began to read.

“Mama? What does it say?” Phoebe moved close to look at the paper.

Diana replied slowly, “He’s saying he’s sorry he got sick. But—”

“But what?” Duncan asked.

“Your Dad wasn’t sick when we put together the time capsule. He wasn’t diagnosed until two years after. This doesn’t make any sense.” Diana was suddenly freezing, as if a door had opened somewhere, sending frigid winds into the safety of her home.

She shuffled the pages, looking for something. But what? There it was. On the bottom of the second page was a date: August 2, 2014. This letter was from the time right before Tom died, not Leap Day 2012. Why was in it the time capsule? What the hell was going on?

“I’m going to read it later, okay?” Her voice caught as she spoke. She slipped the letter and its envelope into her pocket. When the children started to protest, she held up her hand. “This is my decision. Dad left this letter for me.”

“Will you at least tell us what it says?” Duncan asked, gathering the other papers into a pile. He avoided looking at her, and Diana knew he was mad.

“I’ll tell you what you need to know,” she promised. She tried to remain calm, but all she felt was panic.

In The Limits of Knowing, Diana Morgan, a forty-something mother of two living outside Boston, is still reeling from her husband’s death eighteen months ago. One night she and her children open up a family time capsule. Inside, among photographs, report cards, and drawings made in crayon, she finds a letter from her husband, Tom. To her shock, the letter is a deathbed confession—to a crime that he committed when he was eighteen years old.

Tom’s letter disrupts Diana’s precarious hold on her life and her efforts to keep her grief at bay. Her career and children take a back seat to understanding his confession. What was the crime he committed? Why did he keep this secret from her? Why did he finally confess in a letter that she would find only after he was gone? Who was he really? Diana chooses to investigate the letter—an out-of-character choice driven by a need to know who her husband was—and she eventually uncovers the decision he made that filled him with such guilt. It changes her understanding of their marriage. She learns that not only did he cause the death of a man he admired, but he also let someone else go to prison for what he did. Unexpected pressure from old friends to make Tom’s letter public forces Diana to delve even deeper into Tom’s past—including confronting his former lover—and to take action to rectify his mistake.

The Limits of Knowing explores the secrets we keep, the way we’re transformed by grief, and the power of forgiveness.