It is party day at Marguerite Dumont's castle. She sings wholeheartedly, but terribly out of tune. Marguerite has been living her passion in her own bubble, and the hypocrite audience acts as if she was the diva she believes she is.

Lucrèce, the best killer in the business, accepts a final job: eliminate an opera singer who threatens the interests of a corporation. She's hired as a contralto for a festival her target is singing in, but things don't happen as planned.

Based on the experiences of the screenwriter and millions of people around the world, a newlywed photographer is stalked by a dark man in a brimmed hat who follows her from her nightmares and into reality. Sanity slipping, she meets a mysterious man claiming to know the shocking secrets of the Hat Man. It can happen to anyone. It can happen to you.