From the age of twelve, the Baron Cosimo Piovasco di Rondo makes his home among ash, elm, magnolia, plum and almond, living up in the trees. He walks through paths made from the twisted branches of olive, makes his bed in a holly oak, bathes in a fountain constructed from poplar bark. An aerial library holds the books with which he educates himself in philosophy and mathematics. Suspended among the leaves, the Baron adventures with bandits and pirates, conducts a passionate love affair, and watches the Age of Enlightenment pass by beneath him.