Spanning much of the eighteenth and nineteenth centuries, the novel follows the fortunes of the extraordinary Whittaker family as led by the enterprising Henry Whittaker--a poor-born Englishman who makes a great fortune in the South American quinine trade, eventually becoming the richest man in Philadelphia. Born in 1800, Henry's brilliant daughter, Alma (who inherits both her father's money and his mind), ultimately becomes a botanist of considerable gifts herself. As Alma's research takes her deeper into the mysteries of evolution, she falls in love with a man named Ambrose Pike who makes incomparable paintings of orchids and who draws her in the exact opposite direction--into the realm of the spiritual, the divine, and the magical.