When Seth Walker went fishing with his dad, he never dreamed it would lead to the adventure of a lifetime. But after he caught a very large stick (instead of the biggest fish of his life), Seth learned that there’s more to the river than meets the human eye. Seth befriends Mattie the mayfly and takes a tour of the river from a bug’s perspective. He meets strange aquatic invertebrates he never in his wildest dreams imagined existed

a water penny, a wise roundworm, and even an underwater bear! When Seth and Mattie get separated, Seth has to rely on a few newfound aquatic friends and a lot of perseverance to find his way back home and avoid falling victim to hungry predators along the way.