Hanna loves Yann and the lettres filmees that he sends her, short, poetic films recorded with an iPhone. Yann loves Hanna, but mistrusts her. He leaves her, but does not leave her alone. His video-letters become a threat and Hanna does not know whom to trust or whether she can still trust herself. Ma Folie starts as a romantic love-story but gradually turns out to be a complex psychological thriller.