Christine Lucas wakes up every day with no recollection of her life due to amnesia caused by a traumatic accident. Each morning, she believes she is in her twenties, only to be told by her husband, Ben, that she is actually in her forties. Ben patiently explains their life together and informs her about her condition, which prevents her from retaining new memories for more than a day. Dr. Nasch, a neuropsychologist who has taken a particular interest in her case, contacts her secretly and encourages her to maintain a video diary to document her daily experiences and progress.

As Christine starts piecing together fragments of her past through the video diary and therapy sessions with Dr. Nasch, she slowly begins to uncover inconsistencies in the stories told by those around her. Her quest for the truth takes a perilous turn as she probes deeper into her memories, revealing disturbing details about the events leading up to her memory loss. Christine must navigate a web of deception and danger, unsure of whom to trust or believe, as she gets closer to uncovering the reality of her situation.