The world is a dangerous place for a young beaver. Jack, along with his three siblings, learns quickly that even their lodge is not always safe. Bears, wolves, bobcats, trappers, and even birds of prey are a constant threat to the young kits. Mother, Father, the yearlings, and their old uncle all work hard to protect them. Nevertheless, out of the original litter of four, only Jack and his sister survive their first summer of life on the pond.
As Jack matures, he quickly becomes a working member of the colony. While he is expected to protect his mother's new litter, he also learns to fell trees, repair the lodge, and foil the trapper's snares. One day Jack will set out alone on a long journey of discovery. It is time for him to leave the colony, find a mate, and establish a home of his own.