Some suffered visible injuries, some have battled through unseen anguish that lingers a year later.
Many who were touched by the bombings last April 15 found solace in running; some earned entry into this year's race by writing essays. They will line up in Hopkinton on Monday morning to take yet another step toward healing.
Here are a few of their stories:
Sabrina Dello Russo, running because her friend can't
They were intoxicated by the brilliant blue sky, by the afterglow of a spirited matinee at Fenway Park. As they leisurely strolled from Kenmore Square to the marathon finish line, the vibe of a most treasured Boston afternoon -- Patriots Day -- pulsated through the city.
Roseann Sdoia turned to her friend and declared, "Let's run next year.''
"Yes,'' Sabrina Dello Russo responded enthusiastically. "We can do this!"
They discussed it at Forum Restaurant on Boylston Street, where they tracked the progress of their friend Jen Amstead. As she drew closer to the finish, they plopped their drinks down and informed the bartender, "We'll be right back.''
The women gathered in front of Forum with additional friends. Sabrina stood behind a mailbox near the entrance, with Roseann to her right. Photographs would later show Roseann Sdoia was 10 feet from Martin Richard and his family.
As Amstead turned left onto Boylston from Hereford Street, the first bomb exploded.
"We all kind of flinched, because we could hear it and feel it,'' Dello Russo said.
Roseann would later say she thought it was a celebratory cannon, an odd departure from the marathon tradition she knew so well.
Their friend Megan Lawrence screeched, "We've got to get out of here!" yet Sabrina remained eerily calm. "I'm not going anywhere,'' she thought. "I'm going to take Jen's picture crossing the finish line.''
Within seconds, the second bomb blew Dello Russo backwards. The force wrenched the phone from her hands and slammed her to the pavement.
As she lay on the ground, Sabrina looked to her left and saw people running, shouting, panicking.
"But when I looked to my right, I saw something different,'' Dello Russo said.
There was no movement, no sound, just bloodied bodies, some with severed limbs, lying still on the pavement.
Sabrina Dello Russo isn't sure how long it took for her to finally sit up.
"But when I did,'' she said, "my friends were gone.''
Some jumped the barrier into the street. Megan retreated to a nearby store.
Roseann was nowhere to be found.
In the frantic minutes that followed, Sabrina and Megan re-connected and called their families. They received a text informing them Roseann was seriously injured, and headed for Mass General Hospital.
Sabrina, who had shrapnel embedded in her jeans but not in her skin, was diagnosed with a concussion. She waited at Mass General Hospital for news of her friend, who was in surgery. Finally, at 8 p.m., she was told Roseann was OK.
Her surge of relief was quickly dampened by the news that Roseann's right leg couldn't be saved.
"That didn't fit my definition of OK,'' Dello Russo said.
Roseann was their ringleader and Sabrina's personal cheerleader. Every race they did together, Roseann finished before her and waited to greet her with a high five and the same encouraging words: "You did good.''
It has been a long year for Roseann Sdoia. She has good days and bad days, but has managed to handle her handicap with humor, penning her prosthetic "the sucker.'' She lives on the second floor of a North End walk-up, which was never a big deal before, but in the aftermath of her traumatic injury became a challenge.
Sabrina Dello Russo has recovered physically from her head injury, but the nightmares persist.
Last week, she dreamed she was looking out her office window and saw a billowing plume of smoke. She frantically urged co-workers to get out. They ignored her.
"None of them saw what I saw,'' Sabrina said.
Sabrina Dello Russo will run the 2014 Boston Marthon on Monday. So will her friends Megan Lawrence and Jen Amstead, who was stopped 30 feet from the finish line last year.
Roseann isn't sure if she can bring herself to go.
"She'll wake up on Marathon Monday and say, 'You know what? I'm going to get on a plane and go somewhere,''' Sabrina said. "Or, she'll say, 'I'm going to Forum.'"
Training for the marathon has been the most grueling commitment of Sabrina Dello Russo's life. She is 38 years old (though she looks 10 years younger) and has never been this focused or this determined.
"I'm running because I made a pact with my friend that we would do this,'' Sabrina said. "She won't actually be with me on Monday -- but she will be.
"She doesn't like to talk about our training and how hard it is or how fun it is, because she can't be a part of it. But I know in my heart she will be thinking of me.''
Sabrina knows Roseann will be tracking her, on the day that used to be their favorite of the year.
Whether it's in person or by text, she will wait for a simple message from the woman she will honor on Marathon Monday: You did good.
Katie Pratt, running to find peace
Katie Pratt couldn't decide.
Should she watch the 2013 Boston Marathon in her hometown of Wellesley where, as a little girl, she frolicked up and down Washington Street applauding the runners? She had been invited to join friends at Kenmore Square, as well as a group that was congregating for a fundraiser at The Forum on Boylston Street.
"At the last minute I figured, 'Oh, I'll buy a ticket for The Forum,''' Pratt said.
It would be a fun and exciting change to watch from the finish line, she figured.
Pratt was lounging on the Forum patio when her head was turned by a thunderous boom.
"I thought one of the huge speakers at the finish line had blown,'' Pratt said.
She was mistaken. A bomb had gone off, and within seconds a second one exploded 10 feet away from her, ripping her shoes and sunglasses from her body.
The details of what happened next are hazy. Pratt suffered a concussion and isn't clear on how she escaped serious injury, save for a deep cut in her foot and some permanent hearing loss. She simply cannot remember many details, although she later caught a glimpse of the carnage in a television news clip.
"They showed the footage in front of the Forum,'' Pratt said. "When the bomb went off, and all these people went flying, my dad said, 'Isn't that you?'''
The images were haunting, unnerving. In the aftermath of the blast, Pratt, 24, struggled to leave her home.
"I had this fear of getting on the train, of going to public places,'' she said. "I thought, 'What's to stop someone from hurting me?'''
Her sleep was interrupted by nightmares of being trapped, waking her to an overwhelming feeling of helplessness. Why was she spared? How could she help those who weren't? Pratt had never run a marathon -- hadn't considered it -- but in the wake of the bombings, she found running to be a welcome relief.
"It was so incredibly therapeutic,'' Pratt explained. "When I'm running I think of the people who lost their limbs, who weren't as lucky as me ... that's what drives me.''
Since the bombings, Pratt has moved to a new apartment two blocks from The Forum. Every morning on her way to work, she deliberately walks past the spot where her life was forever changed.
"I'm not going to let what happened define this city for me,'' she said.
Suspect Dzhokhar Tsarnaev remains in prison. Pratt, who is on the victims' distribution list, did not watch his arraignment and has no plans to attend his trial.
"I have a hard time seeing him [on television],'' she admitted. "He's so young. I just can't understand why he did this.''
She will run the 2014 Boston Marathon with her roommate Lauren Barrett, who was stopped before she could finish the race last year. They will run to honor victims, to celebrate the goodness of first responders, and to move past the horror of a senseless act of terrorism.
"My dad said to me, 'You can't live your life in fear. Then you let them win,' '' she said.
Katie Pratt has completed a handful of her training runs by sprinting across what will be the official finish line of the 2014 Boston Marathon.
Some of her friends fret that might be bad luck. Pratt doesn't see it that way.
For her, it's merely another step toward reclaiming her life, her city, her peace.
Police chief Ed Deveau, running to take back the marathon
Watertown police chief Ed Deveau figured he better listen to his body.
He ran the Boston Marathon for the third time in 2007 and planned to compete every five years. For a man born and raised in Watertown, the event was a part of his DNA, a time-honored tradition that he rarely missed.
"My favorite day of the year,'' Deveau said.
In 2012, when he began training for the grueling 26.2-mile course, his balky knee barked in protest. The knee became so swollen and painful he had to stop.
"This is stupid,'' Deveau declared. "I'm done.''
But that was before so many innocent lives were shattered, before an officer was gunned down in the line of duty, before an 8-year-old boy with a gap-toothed grin was killed when two alleged terrorist brothers set off two bombs near the marathon finish line.
Deveau took that personally. That feeling only intensified when the suspects fled to Deveau's native Watertown. Officers ultimately discovered Dzhokhar Tsarnaev hiding in a shrink-wrapped boat in a driveway less than three miles from Ed Deveau's home.
That night, Deveau decided, he would be part of the 2014 Boston Marathon field.
"I wanted to do something,'' Deveau explained. "That was our marathon. To think that they tried to take that away from us. ... I figured the 2014 marathon would be the best ever, because I know these people, and I know they will rally.''
For as long as he could remember, Marathon Day meant his mom packing lunch and a blanket and Deveau grabbing a football to toss along the route while he waited for his uncle to run past. When he was old enough, he went to Heartbreak Hill with his friends to cheer on the runners.
Deveau was on a JetBlue flight home from Florida with his fiancée when the bombs went off. Just minutes after the plane departed, passengers watching the airline's televisions were interrupted by breaking news.
Bombs at the Boston Marathon. Many casualties, some fatal. The news was parceled out during the long, long flight back to Logan.
"We were trapped on that plane for three hours with no way to contact my department or anyone else to find out what was going on,'' Deveau said. "Everyone on the plane was crying.''
Deveau and his fiancée had been standing at the exact spot the previous year where the first bomb exploded. Their minds started racing. What if we had been there? Who did we know that was there? Is everyone OK? His fiancée later learned her daughter's friends had lost their legs in the blast.
The nightmare continued for Deveau. On April 19, he fielded a call just after 2 a.m. from one of his Watertown officers informing him, "Chief, they're shooting at us and throwing bombs at us.'' One of the marathon suspects was on the loose in his town. Watertown and the surrounding areas were locked down. Deveau immediately thought of his mother in an East Watertown assisted living facility, wondered about his elementary school teacher up the street. He fretted about the students at Perkins School For the Blind.
"My biggest fear,'' Deveau said, "was the suspect got into somebody's house and hurt someone.''
Tsarnaev was eventually arrested without further incident. Deveau said he has never been prouder of his officers.
Deveau will run with 11 of those officers on April 21. Nine of them have never run a marathon.
Ed Deveau is 57 and shouldn't run another one. His knee screams at him daily to stop, but instead he just slows down.
"All I want to do is to cross the finish line before they start sweeping the streets,'' he said.
Ed Deveau's body keeps telling him this is a really dumb idea.
His heart is telling him something else entirely.
Kate Plourd, running because she knows she's lucky
By the time she reached Boston College, Kate Plourd was exhausted, dispirited and nauseous.
"I'm not running Boston anymore,'' she murmured to herself. "I'm going to run easier marathons where I can improve my time and not feel so sick.''
Plourd, a member of South Boston's L Street Runners, considered quitting, but drew strength from her teammates and the encouragement of total strangers who lined the route as she struggled onward.
By the time she completed the 2013 Boston Marathon, her hands were numb, tingly. Her stomach roiled and when she began speaking, she was lisping.
Plourd eventually retreated to a medical tent beyond the finish line, which was teeming with runners suffering from dehydration, cramping or mild hypothermia.
She found a spot in the back, sipped some Gatorade, tried to get her bearings.
That's when she heard the sirens.
So many sirens.
Plourd guessed someone had suffered a heart attack. Minutes later, a race official informed them there had been an explosion. There were serious casualties and some fatalities.
"For those of you who are feeling better, we need you to leave the tent immediately,'' the official said.
Kate Plourd's mind began racing. An explosion? On the T? Who was injured? Many of her L Street teammates were still on the course. She was supposed to meet her fiancé at Max Brenner Restaurant on 745 Boylston Street following the race.
But now Plourd couldn't get anywhere near Boylston. The streets were cordoned off. She had no phone, and no answers. A sobbing Plourd exited the tent and wandered the streets of Boston looking for a familar face. She was still mildly dehydrated and disoriented. Strangers offered to take her into their brownstone, but she was desperate to locate her friends. She boarded the L Street Runners' bus back to Castle Island in Southie. Someone lent her a phone, but there was no service. For the next 40 minutes, she struggled to suppress her rising panic. Did her fiancé go to the finish line as they discussed? Was the explosion an accident, or something more sinister?
She asked the bus driver to turn on the radio.
"No,'' he said.
Kate Plourd knows how lucky she is. She was uninjured and so were the ones she loved.
In the aftermath, she second-guessed herself whether she should have stayed and offered to help in the medical tent. She's tortured herself with "what ifs,'' including the possibility she and her fiancé could have been steps from the second blast had they made it to Max Brenner.
Plourd, a native of San Diego, had run marathons before and usually took several days off to rest her body. But, after Boston, she hit the pavement the very next morning.
"I don't know how my legs were moving they hurt so badly,'' Plourd said. "But it was so cathartic.''
In the hazy weeks that followed, when her boss from her public relations firm asked her for a monthly memo, she told him, "I don't know if I can give you one. I'm not sure what I've done the past month.''
Plourd has one major regret: cursing the Boston Marathon in her lowest moments of the race last year.
"I kind of want to take that back,'' Plourd said. "I can't even fathom losing a loved one. So many people were injured, lost their legs, and they've all been so positive and so hopeful.
"I kept thinking, 'If they can be this way, then so can I.' I wanted to run Boston again. I needed to run Boston again.''
The BAA gave her an entry number after reading her essay, which eloquently explained while she was not as gravely affected as so many victims, she wished to honor them and offer the closure she is seeking herself.
"I'm so grateful for the fact I can still run,'' she said. "Boston is such a special running community. It always has been, even before what happened last year.''
Kate Plourd is feeling strong again -- Boston Strong. One year has passed, and she can't wait to run the most grueling race she's ever encountered.
Dr. Chase Schumacher, running to honor his patients
The urgent page informed Dr. Chase Schumacher that a patient with serious injuries was en route to Brigham and Women's Hospital.
The patient arrived having suffered a complete traumatic amputation and there was no time to ask a lot of questions.
"We did what we're trained to do,'' Schumacher explained. "When you see a patient in need, you go about seeing the problem is fixed. You go into auto pilot.''
As Schumacher and his colleagues soon discovered, the patient was not an isolated victim. Within minutes, a series of ambulances unloaded bloodied patients, many with severely damaged extremities that required tourniquet splints and emergency surgery.
"It wasn't until the fourth or fifth victim went through that I even had a chance to ask, 'What happened here?''' Schumacher said. Thirty-nine of those injured in the bombings were transported to the trauma center where Schumacher was working.
Schumacher had planned to watch the marathon from the finish line that day with friends visiting from his native Louisiana, but he was called into work at the last minute. He expected a busy afternoon, but nothing -- not even extensive emergency trauma training -- could prepare him for what he witnessed that day.
While amputations are not uncommon in hospitals, they are often limited to diabetic or elderly patients.
"This," said Schumacher, "was a totally different patient population. We were treating teenagers, people in their 20s, athletes, newly married couples, an athletic trainer.
"No matter how bad it was, our immediate goal was to save their extremities.''
The single-mindedness required to manage the sheer numbers of the patients, along with the severity of their injuries, prevented Schumacher from reading news reports or viewing television footage of the tragedy. He was simply too busy.
"Almost everyone around the country knew more than I knew,'' Schumacher said. "It was really was about two weeks before I was able to fully take in what happened.''
Once he had a chance to reflect on what occurred, as well as meet with his patients and their families during their ongoing recovery process, Schumacher, who has never run a long distance race, made the decision to run Boston in 2014.
"I felt a calling to do this,'' he said. "I wanted to represent those patients who are still working towards getting back on their feet. I want to honor them, out of respect for them.''
Schumacher was a former high school football and basketball player but only a recreational runner. His busy work schedule has made training arduous, often requiring late-night runs after completing 14-hour shifts at the hospital.
When he's sapped of energy, or lacking motivation to train, he focuses on Gillian Reny, a high school senior and avid dancer who was at the finish line with her mother, Audrey, and father, Steven, waiting for her sister Danielle to cross.
Reny was critically injured in the blast and suffered significant damage to both legs, but after many months and multiple surgeries at the Brigham, she is walking again and enjoying her freshman year at the University of Pennsylvania.
Her grateful family started the Gillian Reny Stepping Strong Fund to help generate research dollars for saving limbs and bone and skin regeneration.
Thanks to the BAA, which chose his essay as worthy of earning an official race entry, Dr. Chase Schumacher will run the Boston Marathon to support both Gillian and the Stepping Strong Fund.
This year, Schumacher will not be on call at the Brigham. He vows to make it to the finish line -- as a runner, a medical advocate and a symbol of hope and healing.
Athletic trainer Adrian Wright-FitzGerald, running for victims
The day was running so smoothly. Adrian Wright-FitzGerald wasn't sure what to expect when she volunteered to work the "A" medical tent at the marathon finish line, and while there was a steady stream of patients for lower body injuries, blisters, cramping and mild hypothermia, for the most part, it was an easy, manageable, inspiring day.
"I was having a really good time,'' said Wright-FitzGerald, who is a certified athletic trainer.
Just before 3 p.m., as she knelt down to assist a runner, she felt the ground shake.
One physician surmised it was a truck collision; another claimed a major thunderstorm was coming.
"And then, all of a sudden, the atmosphere changed,'' said Wright-FitzGerald.
In a matter of moments, there were screams, sirens, anguished cries of pain. The medical personnel were simply told there was an "incident" with casualties.
"No one mentioned the word 'bomb,''' she said.
The tent suddenly resembled a war zone; a bloodied police officer in a wheelchair, spectators on stretchers, some with their limbs severed, victims with seared flesh and burning clothes.
"It just kept getting worse and worse,'' Wright-FitzGerald said.
In theory, Wright-FitzGerald had been trained how to stop bleeding, cover a wound and apply a tourniquet, but in her capacity as an athletic trainer at Bentley University, she had never been asked to administer any of these techniques.
Now she was treating flesh wounds from shrapnel, patients in shock who were losing large quantities of blood, victims whose limbs were partially blown off.
There weren't enough medical gauze pads to handle the demand, so the staff quickly turned to makeshift tourniquets made from T-shirts and towels.
There was little time to consider what was happening. When Wright-FitzGerald finally did, she felt a knot growing in her stomach.
"I remember wondering, 'Why is this happening?''' she said. "It was such a dramatic swing from the patients we had been treating all day, who had minor injuries but were so happy to have finished the race. "In an instant we went from that to fear and terror, treating spectators instead of runners, tearing burning clothes off people's bodies.''
Wright-FitzGerald continues to be amazed by the poise of the medical staff, who remained organized and calm and even after one of the victims who had already perished was wheeled into their tent.
"They are an amazing group of professionals,'' she said.
When the wounded were finally transported elsewhere, Wright-Fitzgerald rummaged for her phone and discovered she had received over 100 text messages.
The police ordered an evacuation of Tent A -- it was now officially a crime scene -- and Adrian wandered into the street, unsure what to do next. She went back to work the next day, incorrectly assuming a return to routine would be helpful.
"I was a zombie all week,'' she said. "I couldn't focus. I didn't have the desire to do anything.''
She received counseling from Bentley's mental health officials, but then a manhunt for one of the bombing suspects centered on Watertown, where she was living, and the lockdown triggered the sirens and the smell of burning flesh all over again.
It has been a long year for Adrian Wright-Fitzgerald. She wishes she had done more to help the survivors. She wishes she could forget what she saw.
"It's been really hard in ways I didn't expect it to be,'' she admitted.
Initially, she struggled to return to treating tendinitis, ACL repairs and muscle strains, which had always been fulfilling and meaningful work to her, but now seemed trivial compared to the injuries she managed that day.
In the wake of the bombings, Wright-Fitzgerald found running to be a welcome relief. She thought about returning to the "A" tent on Marathon Monday as a volunteer, but will run for the survivors and their families instead.
"If I was running any other marathon as my first, it would be exciting,'' Wright-Fitzgerald said. "But this feels 10 times more important.''
The haunting images linger, yet Monday presents the opportunity for a new narrative, a new beginning.
And, more important, a better finish.
Editor's note: MacMullan's vignette on runner Katie Pratt first appeared this week in an earlier marathon feature.