Hanna loves Yann and the Lettres filmées. Poetic-essayistic short films recorded with the iPhone, which he sends her. Yann loves Hanna, but he doesn't trust her. He leaves her, but he no longer leaves her alone. His Lettres filmées suddenly become a threat and Hanna doesn't know who she can trust anymore - or whether she can still trust herself. »Ma Folie« begins as a romantic love story, as a passionate amour fou, but gradually develops into a multi-layered psychological thriller in which the boundaries between self-perception and perception of others, trust and mistrust, reality and illusion, truth and lie become blurred.