A young girl goes for a ride with her father one night when her mother is at Bible study. They pass a neighbor walking barefoot along the dirt road. The father stops to pick up the woman and offers her a ride back to her trailer. But first he lets off his daughter at home. Two years later, the girl is out for a walk on a sweltering night when she sees a man drop a baby down a well. Thus begins Kalisha Buck hanon’s ambitious third novel, “Solemn,” which centers on the effects of that murder on the young girl, Solemn Redvine, and sweeps outward to examine the lives around her.