Southernmost opens with a devastating flood in Cumberland Valley, Tennessee. Could it be divine punishment for the Supreme Court's legalization of gay marriage? Thirty-five-year-old Asher Sharp, a Pentecostal pastor, has a shaky faith that has been diverging from his wife Lydia's fundamentalist certainty for a while now, but the flood and its aftermath provoke a crisis that changes things forever.

When Asher goes in search of his eight-year-old son, Justin, who ran off to search for their dog, he gets pulled into a rescue effort. A floating house is about to slam into a bridge with Caleb Carey, a deacon from Asher's church, and his family stuck inside. Jimmy, a Nashville songwriter new to town, finds Justin and then helps save Caleb and his daughter. Meanwhile, Jimmy and his partner Stephen's house has been washed away. Asher tries to extend hospitality by giving ...