9-year-old Walker Myrick is a twin but his brother died during mom's pregnancy. Walker and his mom visit his brother Willis at his grave for every holiday. The two, even though they never met, still share a brotherly bond. Willis died from a rare condition called Twin Transfusion Syndrome where both babies share a placenta. Now every year their family participates in the 'Walker and Willis Birthday Walk' to help raise awareness about its complications.