Set in a picturesque valley, the town of Riverton is an ideal place to live, unless you're a Nimrod. If you're a Nimrod, you live in the hills or flee the valley, because the Nimrod Ghost has been haunting the Nimrods for over a hundred years. It all started when the orphan Ezekiel sat on the Riverton bridge, reading a book. Noah Nimrod pushed him into the river, for no other reason than Ezekiel could read, and Noah couldn't. Unfortunately, Ezekiel couldn't swim... and drowned. Ezekiel was so angry at Noah that his ghost followed Noah around town, yelling at him, until Noah was old enough to move into the hills. And that's where the Nimrods stayed, because Ezekiel stayed in town, ready to haunt any Nimrod who dared set foot in Riverton. But one day this changes when recently-turned-ten Rose Flowers sits on a Riverton bench reading a library book, and happens to notice Ezekiel reading over her shoulder. Ezekiel, tired of being alone and delighted that someone other than a Nimrod can see and hear him, figures out a way to follow Rose home. Unfortunately, home is right next door to the Nimrods, and Curtis Nimrod is not pleased with his new neighbor. But over the summer, an unlikely trio of friendship develops between a ghost, a girl, and a boy.