Aaron is not a man on a hero's journey. In the question of fight or flight, he'll choose flight every time. So when a car accident leaves him suddenly asymmetrical, his left arm amputated, looking on the bright side just isn't something he's equipped to do.
Forced to return to his boyhood home to recuperate, Aaron is confronted with an aging father (a former Olympic biathlete turned hoarder), a mother who's chosen to live in a yurt with a fireman 12 years her junior, and a well-meaning sister whose insufferable husband proves love isn't just blind but also painfully stupid.
As Aaron tries to make the world around him disappear in a haze of Vicodin and medical marijuana, the only true joy in his life comes from daily 90-second radio spots of fun science facts: the speed of falling raindrops, batteries made out of starfish, and sexual responses triggered by ringtones - all told in the lush, disembodied voice of commentator Sunny Lee, with whom he falls helplessly, ridiculously in love.
Aaron's obsession with Sunny only hastens his downward spiral, like pouring accelerant on a fire. Pressured to do something - anything - to move his life forward, he takes the only job he can get. As a "fish counter" at the nearby dam, he concludes that an act of violent sacrifice to liberate the river might be his best, final option.