Franny, a young fish born in the Grand Canyon, finds herself in the cold, clear waters released from a major dam. In order to find her place in the river, Franny the flannelmouth sucker adventures down the length of the Colorado River in the Grand Canyon, avoiding predators, rapids, and an ever-changing river along the way. Throughout her journey, Franny becomes more confident and comfortable, finally finding the place in the river where she feels most at home.

Franny's story, although fiction, is informed by science. Flannelmouth suckers grow best in clear, warm water, and in areas where there is plenty of algae available to eat. Notes at the end of the story provide factual information about flannelmouth suckers and the other animals Franny encounters during her journey throughout the Grand Canyon.