It's 2053. Helen Banis is 100 years old and is preparing to die, a preparation that she began 20 years earlier, when she retired from her career as a librarian and moved to the remote property she and her husband had bought in 2020, anticipating a time when they and their three grown children and their children might need a place to retreat to if the climate crisis continued to intensify.

Her son, Raven, comes to the property to check up on her, but she's not there. His two sisters and his niece join him to search for her, believing she must be injured or dead. They find journals she has been writing, and from what they read, they suspect she may be suffering from dementia. The longer they stay at the property trying to find out what happened to their mom, the more the mystery deepens, as characters real or imagined appear, and they begin to question the reliability of their perceptions.