There's nothing that Wade and his younger brother, Andrew, love more than fishing together. As summer draws to a close, they're excited for one last hoorah before classes begin and they end up at different schools for the first time. But a typical fishing trip with their best friends, Camilla and Tommy, quickly takes a darker turn. As heavy fog creeps over the creek, Andrew hooks something big--too big. In a moment of chaos, the brothers end up overboard. There, in the murky depths, they get a glimpse of what waits at the end of the line. And it seems far more monster than fish. Wade and the others wonder if the recent hurricane that hit the area may have stirred up more than just water, unleashing something horrible from below. Their parents don't believe they saw anything at all. But if there really is something out there, the kids know someone needs to stop it. So, they decide to do what they do best and go fishing for their biggest catch yet: evidence of a real-life river monster. Will these four friends be able to prove everyone wrong and save the creek, or are they about to discover they're in way over their heads . . . and in deep trouble?