Upon the Great Plains, during a time that only our ancient ancestors could know, there lives a species that thrives in seas of herds: bison, or Free-Roamers, as they call themselves. The Ice Age has ended, and with the birth of today"s modern bison, Prairie, a calf, is nestled in the heart of the plains in a valley known as the Sun Bowl. It is there where she grows up, but under an array of unnerving circumstances--the mysterious vanishings of several male calves, including her close friend Thicken--she leaves the safety of her homelands and travels out into the vastness of the Great Plains. Soon finds herself traveling the distant lands to fulfill a promise, and possibly a strange lore. Unbeknownst to her, Thicken and her father Blackmor, the leader of a famous bachelor-group, are working to settle things with the strangers who steal young bulls. A storm of unusual events is churning that could defy their species" future, and that has always intertwined Prairie with a rather eccentric family tree.