Would you agree to give a kidney to a stranger if your loved one in need was promised a kidney in return?
This is the pay-it-forward principle that came from Jan and Garet Hil after their 10-year-old daughter Samantha suffered from double kidney failure.
The Hils hit roadblock after roadblock in their search to find Samantha a donor.
In the end, her 23-year-old cousin was a perfect match and willing to donate his kidney.
But after their stressful experience, Samantha's parents wanted to help other families like them and started the National Kidney Registry.
Reported by Katie Couric on the CBS Evening News, the website has "nearly 100,000 records of people who need kidneys and their loved ones willing to give up one of theirs to anyone who promises to keep the donor chain going."
Since 2008, 195 transplants have been facilitated. Today, the longest chain of kidney swapping yet is taking place. Twenty-eight lives are expected to be saved.
Watch the video to learn about some of the people who have been saved thanks to the National Kidney Registry and the kindness of strangers.