Clara, a lonely and desperate nurse from the outskirts of Sao Paulo, attends a job interview for a live in Nanny with the elegant and pregnant Ana. Although the difference in these women’s classes and backgrounds are undeniable, Ana decides to hire Clara. As the two begin to open up to each other, a strong bond and wary attraction develops between them. Ana tells Clara about the night of her unborn child’s conception; a mysterious stranger, a full moon and a strange creature glimpsed in the night. Complications soon arise, and Ana is afflicted by strange pains along with cravings for bloody meat and midnight ramblings. One night, Clara follows her out into the city during a nocturnal stroll. What she witnesses alters Clara’s destiny, while the true nature of what is gestating becomes apparent.