Abby Hudak still remembers the moment her life changed.
At 30, the lifelong athlete began experiencing unusual symptoms -- shortness of breath, night sweats and vision blackouts. Within hours of going to the emergency room, she was diagnosed with acute lymphoblastic leukemia.
"I had never even spent a night in the hospital before," Hudak told ABC News. "And suddenly I was there for a month."
Her treatment began immediately, but doctors soon determined she would need a stem cell transplant -- her best chance at a cure.
Months later, Hudak learned a stranger had been identified as her match.
"I knew he was a 28-year-old male, but that was it," she said. "And even then, there’s always a chance something could change."
That stranger was Lewis Haggerty, a donor from Scotland who had signed up years earlier at a university fair.
"I didn't think I was doing anything extraordinary," Haggerty told ABC News. "It just felt like the right thing to do."
After undergoing health checks, Haggerty donated stem cells in 2023 through a process he described as "very straightforward," similar to giving blood over two sessions.
For Hudak, the transplant marked the beginning of a long and difficult recovery, not the end.
"It's a misconception that you're done after the transplant," she explained. "Your body is essentially starting over."
Hudak spent a month in the hospital and continued treatment for years, dealing with complications, nausea and the physical and emotional toll of cancer. She said the experience also came with lasting impacts, including infertility.
Still, she said she made a conscious decision early on to focus on what she could control.
"While I was in the hospital, I created a bucket list," she said. "I wanted to focus on living, not dying."
Now 34, Hudak works with the National Marrow Donor Program, helping guide potential donors through the same process that saved her life.
According to the organization, a blood stem cell transplant can be used to treat or cure more than 75 diseases, including leukemia, and about 75% of patients do not have a fully matched donor within their family.
For Hudak, the impact of one donor extends far beyond her own life.
"When Lewis donated to me, he didn't just save my life," she said.
For two years after the transplant, Hudak and Haggerty remained anonymous to each other, as required. It wasn't until later that they were able to connect -- first through messages, then a video call.
Finally, about three years after the donation, they met in person for the first time at Walt Disney World earlier this month.
"It felt so natural," Hudak said. "Like we were already family."
Haggerty described the meeting as emotional and surreal.
"It took something abstract and made it real," he said. "You realize you've helped a real person with a real life and a real family."
The pair spent several days together with their partners, bonding over shared interests and laughter.
To mark the moment, they ran a 5K together during a runDisney event -- an idea Hudak had envisioned even before they met.
"We just laughed the entire race," she said. "It was a celebration of everything we’ve both been through."
For Haggerty, traveling from Scotland to join Hudak was an easy decision.
"To see how far she's come, from being so unwell to running a race, it was incredible," he said.
Today, the two say they are forever connected.
"She has my DNA," Haggerty said.
Both said they hope their story encourages others to consider becoming donors.
"You can have a bigger impact than you can ever imagine," Hudak said.
Haggerty added that the process is simpler than many people think.
"If you’re healthy, it's a small thing you can do that could save someone's life," he said.
Hudak also shared advice for others going through cancer, emphasizing the mindset that helped her through her most difficult moments.
"Find your mental peace… find what you do have control over," she said.
The Walt Disney Co. is the parent company of ABC News.