On "gma" we like a good medical story and partial to love stories. Rarely, though, can we combine the two. At the center of this one is a 17-year-old who learned he needed a new heart. He could never... See More
On "gma" we like a good medical story and partial to love stories. Rarely, though, can we combine the two. At the center of this one is a 17-year-old who learned he needed a new heart. He could never imagine what else he would get along with that. Life-saving gift. Erik johnson of komo has the story. Reporter: She likes to put her head to his chest and listen to his heartbeat. Steady. Reporter: Aaron knows what he knows that this heartbeat can never be taken for granted because it is made possible a very special kind of love. I they hanever thought I could be so in love with another person. I have no words to describe it. Reporter: Many at 17 he had been a star catcher being recruited by division 1 schools life changed in 2005 when they told him he needed a new heart. If he didn't get one he would die. Kellan roberts was a seattle kid, generous to a fault, a free spirit women cal and spontaneous drove his red truck all over the country, lived life on his terms. He traveled all over the world. He traveled the united states. He jammed in as much as he could and left a much better legacy for us. Reporter: March 7th, 2005 on a trip to sioux falls, south dakota, kellan hit his head in a freak accident died far from home but not far from minneapolis. He was an organ donor. Scared. We drive to the hospital and they were going to cut me open and take my heart. Reporter: The transplant was a success, the engine of life had passed from one man to another. I just wish he could know how grateful I am. Reporter: Connor wanted, needed to know about kellan. I was so grateful, but so -- you know, I'd give it back in a second. Reporter: Aaron more than anyone understands what's in connor's heart. Erin you see was kellan's sister. It's priceless to know that a part of something you love so much can continue on and not just continue on in existence but be the life force for someone else. I don't know if there's any words to describe that. Reporter: They say they fell in love almost immediately. Instantly. I have a vividly in my head just looking over, feeling her mom hug me and just staring in her eyes. Reporter: To some it's a strange love. Buey had to give it a shot. When you are young and in love, you follow your heart. Erik johnson, komo 4 news. Extraordinary. Tears. Incredible story and our thankomo for bringing it to us.
This transcript has been automatically generated and may not be 100% accurate.