portrait of strength and spirit. Tuesday marks one year since the terror attack on the Boston marathon. And a mother is making a comeback with a message of hope. Here's David Muir. Reporter: It was a... See More
portrait of strength and spirit. Tuesday marks one year since the terror attack on the Boston marathon. And a mother is making a comeback with a message of hope. Here's David Muir. Reporter: It was a moment we will never forget. In that hospital room Celeste Corcoran, a devoted mom and wife, and a double amputee after the Boston bombings, about to be paid a visit. Marine Gabe Martinez telling Celeste at the time, this is not the end. This is a new beginning. And listen closely to what she told him. I can't do anything right now. Right now, yes, but I'm telling you, and with all my heart, you are going to be more independent than you ever were. That means -- I'm so glad to hear. Reporter: Wiping away her tears as the marine promised bright days ahead. Afterward, offers of help pouring in from all over the country. Then, video from the family, a mother determined to not let the terrorists win. Reaching a milestone on the treadmi treadmill. And look at this. The physical therapists at prosthetic and orthotic associates in Orlando helping her run, each holding straps to keep her upright. A struggle at first, but she finds her way. You can hear loved ones, stunned. Now climbing to heights unimaginable that day in the hospital room. One more grip to the top. Unbelievable. Reporter: They sent us photos of that first run in that rehab center, with no straps, no help. The first time that I did it myself like I literally kept saying to myself, I can't believe I just did that. I can't believe I just did that. I just did that by myself. Reporter: Every step celebrated by the husband who helped save her the day of the bombings. She's the glue that holds our family together, without a doubt. She is my inspiration. She's a lot tougher than I am. Reporter: And she called us that night. She bought a new car, celebrating with a margarita. Knowing in the days ahead, she would learn how to drive again. All of this steering her back to where this journey got its unexpected and horrible start. Near the finish line of the marathon, where she'll be back with her daughter, who she nearly lost in the bombings, waiting for her sister, the runner she was cheering on a year ago. My dream is to be at the finish line. I think of us just holding hands and just crossing the finish line. The three of us together. So we chose Se lest with thanks to David Muir. Tomorrow, dream own, stories of Boston's strongest. We thank you for watching tonight.
This transcript has been automatically generated and may not be 100% accurate.