Because We Forget Everything

M, a mystery writer, has a girlfriend of five years named F. After an especially busy few weeks, he loses contact with her. Then a woman claiming to be her sister reveals that his girlfriend has been missing since Halloween. M begins the search for his girlfriend, but the people he meets along the way describe a woman very unlike the F he knew. Moreover, his own quiet life begins to change as his search drags him into other people's problems. (Hulu)