"Unforgettable" follows Carrie Wells (Poppy Montgomery), a former police detective that has a memory that is flawless and can remember every place, person and thing. However, there is one thing that she can't remember. That is the details that could solve her sister's murder that happened a long time ago. Carrie has tried everything she could do to put it behind her, but when she is reunited with her ex-boyfriend Al Burns (Dylan Walsh) and partner when she is a consultant in homicide case. Carrie starts to feel at home being on the case and decides to be with Al's unit as a detective. Meanwhile, on her off time, she researches the clues from her sister's murder. She just needs to remember the details.