Unforgettable follows Carrie Wells, a former Syracuse police detective who suffers from hyperthymesia, a rare medical condition that gives her the ability to vividly remember almost every detail of her life. After witnessing a murder in her neighborhood, she reluctantly joins forces with her ex-boyfriend and former partner, Lieutenant Al Burns, to help the NYPD solve complex homicide cases. Utilizing her exceptional memory alongside traditional investigative work, Carrie tackles difficult crimes while secretly searching for the one crucial memory that continues to elude her: the details surrounding her sister's childhood murder. Over the course of its multi-network run, the series shifts dynamics as Carrie and Al relocate to New York City's Major Case Section, working alongside a rotating team of talented detectives. The procedural drama balances high-stakes murder investigations with deep psychological character studies, exploring how a flawless memory can be both an invaluable asset and an emotional burden. The central tension consistently revolves around Carrie's quest for justice and closure, blending classic whodunit mysteries with serialized personal arcs.