Nessa Vale, a temporary keeper at an automated coastal lighthouse, discovers that the facility is transmitting signals from ships missing from every official registry. As she enlists a maritime historian to help decode these anomalies, she uncovers a haunting link to her own family's history. Set against a backdrop of escalating isolation and salt-weathered mystery, this seven-part correspondence explores the burden of memory and the preservation of the lost, culminating in a poignant decision about the lighthouse's future.