Tess is a 36-year-old business owner who wakes up daily with no memory of the past seven years. She founded a highly successful company called My Home Spa but now spends her days confined to her house due to a brain injury. She relies on a handwritten letter to ground her reality, though her physical reactions and instincts often conflict with the information she reads. She tries to piece together her fragmented past while managing constant surveillance.

Graham is an accountant who currently manages My Home Spa on his wife's behalf. He dictates Tess's schedule, diet, and access to the outside world under the premise of keeping her safe from wandering. He enforces strict daily routines, maintaining high security measures around their home with padlocks and tall fences.

Harry is Tess's former fiancé and the original owner of a pet finch named Ziggy. According to the letters Graham provides, Harry committed an unforgivable act that ended their engagement years ago. He actively attempts to reach Tess to warn her about her current living situation, wearing a beard and a baseball cap to avoid immediate detection.

Lucy is Tess's college friend who now works at My Home Spa. She serves as a primary source of information about Tess's missing years, assuring her that Graham is an excellent partner. She freely navigates the Thurman house and shares a casual familiarity with Graham, though her explanations sometimes contradict Tess's lingering feelings.

Camila is a young woman employed as Tess's daytime companion and babysitter. She ensures Tess stays within the property lines and intercepts any attempts Tess makes to run away during errands. She shares stories about watching telenovelas with her grandmother to build rapport with Tess while strictly enforcing Graham's rules.

Ziggy is Tess's dog, sharing a name with a bird Harry once owned. He is kept outside because Graham claims he chews the furniture. He instantly bonds with Tess every morning but displays highly aggressive behavior whenever Graham approaches.

Douglas is Tess's father. He is reportedly away on a cruise, making him completely unreachable when Tess leaves desperate voicemails seeking clarity about her missing years and sudden marriage.

Pete is a security guard working at the local grocery store. He intervenes when Tess attempts to slip away from Camila, treating Tess as a confused wanderer based on Camila's explanations of her mental state.