Emma is a young woman who accepts a solitary housesitting job on Strand Beach following a devastating car accident. She struggles with intense grief over the loss of her infant daughter and isolates herself from her previous life in Salt Lake City. To pass the time, she reads poorly written e-books and takes long walks on the beach with her dog. Her emotional trauma causes her to experience intrusive memories and contemplate ending her own life.

Deacon is a retired author who lives in the only other occupied house near Emma's isolated rental on Strand Beach. He previously achieved success with a true crime novel but currently lives quietly, spending time observing his surroundings. He initiates a long-distance acquaintance with Emma and recommends a specific e-book for her to read.

Howard is a man with a troubled past who previously spent time living in the same remote, glass-walled house where Emma now stays. He harbors a deep interest in the writing profession and has a complicated history with the local retired author, Deacon Cowl. He struggles with his mental health and holds intense, lingering fixations.

Jules owns the modern, glass-walled house on Strand Beach where Emma stays. She lives in Portland and manages the property remotely, relying on a system of cameras and alarms to monitor the location. She acts quickly when she detects unusual activity on her doorbell camera, ordering protective equipment for her housesitter.

Shawn is Emma's husband, who remains in Salt Lake City while she stays on the coast. Before the tragic car accident that fractured their family, he shared a happy life with Emma, pursuing hobbies like painting miniature mountains for his train sets. In the present, he exists largely in Emma's mind as she remembers his encouraging phrases and past support.

Shelby is Emma and Shawn's infant daughter. Her death in a highway collision serves as the catalyst for Emma's retreat to the Pacific Northwest. Though she is no longer living, her memory constantly shapes her mother's daily struggles and emotional state.

Laika is Emma's golden retriever, named after the famous space dog. She serves as Emma's sole physical companion at the isolated Strand Beach house, accompanying her on daily walks and reacting to disturbances outside the house. She provides unconditional affection during Emma's period of profound depression.

Jake is a local delivery driver tasked with bringing a package to the isolated property on Strand Beach. He often works while listening to headphones, which leaves him somewhat disconnected from his immediate surroundings as he completes his route.

Laura is a teenage girl who went missing in the Strand Beach area years ago, leaving a lingering shadow over the small community. Her unresolved disappearance remains a topic of local discussion and adds to the ominous atmosphere of the isolated town.

Eric is a local police officer who patrols the Strand Beach area. He responds to calls regarding suspicious activity and conducts routine wellness checks on the isolated properties. He possesses a pragmatic approach to his job and draws on his personal experiences with grief when interacting with distressed residents.