Set a decade in the future, "Vigil Harbor" interweaves the lives of the inhabitants of a coastal town facing the ravages of climate change and the undercurrents of personal and political dramas. Architect Austin Kepner designs homes to combat the fury of increased storms while recovering from his stepson Brecht's traumatic narrow escape from terrorism in New York. The arrival of two mysterious outsiders—a charming stranded traveler and a widow investigating a past alliance—destabilizes the precarious balance of community life. As concealed motives are unveiled, a critical incident poses a threat to many, including Brecht, and forces the town to confront the convergence of human desires with the profound mysteries of nature and existence.