The River Why is a 2010 American independent drama film directed by Matthew Leutwyler. It is an adaptation of the 1983 Sierra Club novel of the same name by David James Duncan and stars Zach Gilford, William Hurt and Amber Heard. The River Why is an adaptation of the 1983 Sierra Club novel by David James Duncan. The coming-of-age tale centers on a young man named Augustine "Gus" Orviston (Zach Gilford) and his quest for an elusive rainbow trout, which is a metaphor for the man's internal search for self-knowledge. Amber Heard plays his love interest, a tomboy fly-fisher named Eddy.