Sometimes chance brings us together with the people who'll come to mean most to us in the strangest ways. Like the way it brought together Liana Banner and Nate Harden: She was an interior designer from New York, come home to her family's suburban farmhouse for the summer to rest, recuperate, and recover. A few weeks of home-cooked meals, sun-drenched afternoons, and dips in the local pond would cure the ills that ailed her. The pond was on the neighbors'...