Doctors told Kristen McAllister she would never walk again after an infection severely damaged her spinal cord. 

“It started with my left foot," she said. "I just remember I was walking into the bathroom and it just wouldn’t pick up."

Paralyzed from the chest down, Kristen had to start over. 

Kristen, who graduated from Farragut High School in 2013, had always been active. She was a swimmer, she played softball and was a competitive gymnast. 

In June 2015, though, the infection set in. 

“I had to learn how to do everything again. I couldn’t reach anything, I couldn’t stand up, I had to make sure my clothes weren’t on too tight because it could cause damage to my skin," Kristen said.

Doctors gave varying diagnoses, but all agreed that Kristen, then 19, would spend the rest of her life in a wheel chair.

"I just remember breaking down like, woah," she said. "I've never been that sad in my life." 

However, doctors missed something that cannot be diagnosed - Kristen's spirit.

"I’m a little stubborn and so I was like no, that’s not going to be me I’m going to walk again," said McAllister, who is now 21. 

She found a therapy center in Maryland specializing in spinal cord injury. There, she worked to learn what used to come naturally. 

“I remember telling my parents, I’m not giving up and I’m not going to stop therapy until I walk," she said. 

“Because I believed that I could, I am now walking with a walker.” 

Still following her dream of learning to walk without a walker, Kristen learns new techniques through sessions with her therapists. However, her therapists say they learn just as much from her. 

“She comes in with a big smile on her face and she never ever lets it get to her," said Beth Melancon, one of Kristen's local therapists at Patricia Neal Rehabilitation Center.

"She has inspired me to be a better therapist. Her joy is contagious." 

On a mission to walk without assistance, Kristen stays busy with weekly therapy sessions. One day, she hopes to open a gym for those with spinal cord injuries with a policy to never give up on a client no matter how severe the injury. 

“You can't give up. Never give up," said Kristen. 

"If no one is giving you hope around you, you have to give yourself hope and you have to believe in yourself because if you believe in yourself, that will show everyone else that they believe in you."