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.
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.''