When you meet 3-year-old Avery Cook, you'd never guess that when he was just 8 months old, he was fighting the biggest battle of his life.

“We were actually on a family vacation during Christmas time,” Avery’s mother, Bailey, said.

A fun time turned somber quickly when bath time came around.

“I sat in the tub with him. ... The way the light hit his back, you could see how bruised he actually was. That’s when we knew something was actually up. Something was wrong,” Bailey Cook said.

Avery was soon diagnosed with acute lymphocytic leukemia, the most common type of leukemia for kids.

“It went from, 'Oh OK, this is my normal everyday life,' to 'This is my new life; this is what were going to do,' " Bailey. said.

After rounds of chemo, Avery went into remission. But the Cooks, of Hernando County, were not out of the woods just yet.

“We were literally two weeks away from being outpatient to where we could come home all the time, and in that little bit of time, he backtracked, got cancer again. But it had mutated itself into AML (acute myeloid leukemia),” she said, fighting back tears.

“It was really hard. Even the doctors said it’s pretty rare for this to happen, so they didn’t really have a protocol for his cure,” husband Austin added.

The only solution to help Avery at that point was a bone marrow transplant, which, little did they know, would come right around the corner near "The Most Magical Place On Earth."

A viable donor lived in Orlando, but the Cooks didn't know it until just a few weeks ago.

Avery received bone marrow from a donor named Jamie last year. Since then, he's back to the happy little boy he’s always been.

“It’s just not enough to tell someone who saved your only child’s life,” Bailey said.

The Gift of Life Marrow registry helps cancer patients find a donor. To find more information on how you can get involved, click on the link to its website.