Four years ago, Dan Peterson was in his darkest days. His wife had just died, he was severely depressed, and was out grocery shopping for himself in Augusta, Ga., when he was spotted by four-year-old Norah Wood, who said, "Hi, old person!" and demanded a hug. The two struck up an unlikely friendship which continued through Norah's kindergarten graduation and weekly visits to his garden, with countless hugs along the way, even up to the day before Dan died last month at age 85. Steve Hartman revisits the friendship that touched the world, which offered a prescription for happiness.