A long time after the Big Bang, but long before giant reptiles first began to swim about the watery oceans of our planet, there is a little-known segment of Earth's history. This era, this unrecorded time, is known to those who study it as Early Earth. Isabel Greenberg has created an entire world, and populated it with gods, monsters - and humans, creations of the great god of Early Earth, BirdMan, and his two children, the Ravens, who delight in meddling in their lives.