I remember driving through Missouri River bottomlands on the Yankton Sioux reservation on the summer solstice. Dusk faded slowly and the air was full of fireflies as the sun took forever to set. We stopped by a bridge to get our bearings, reading the map by the last rays of sunlight. Somewhere past 9:30 it was finally nighttime and we slunk through Nebraska on the south side of the river in the dark, the air fragrant with loam and alfalfa and slow water.