The World Tree in Rome, Italy has fruit that is actually new worlds being born – small planets hang like apples from its branches. Each world contains an immense amount of concentrated power, and Felldrake wants it. The Caballeros track him to Italy and ascend the tree, but discover Felldrake has transformed the tree's termites into terrifying monsters the size of rhinos. The resident Roman gods are revealed to be peaceful gardeners and lumberjacks, afraid of the termites and useless in battle against them. The Caballeros must act as super-exterminators. If they fail, the tree connecting all the worlds will be eaten away, and the universe it holds in its branches could collapse.