One summer morning, 12-year-old Arnold Hillerman and his 17-year-old brother Eugene wake at dawn on their family's Montana farm. In a nearby pasture, Arnold's gun fires accidentally. His brother is killed instantly. Isolated by emotions he can't comprehend, Arnold must now come to terms with his grieving family - including his angry father, his frightened mother, his antagonistic uncle and his gentle, straight-talking grandfather - while his family must come to terms with Arnold.