The TV series "The Perfect Nanny" is a thriller based on the novel "Lullaby" by Leila Slimani. A couple raising two young children is in search of a caring and responsible nanny. Charming Louise arrives for an interview. She is attractive, polite, has good experience, and simply adores children, leaving no doubts in the minds of the protagonists. However, gradually Louise's excessive and even intrusive care begins to raise their suspicions. The nanny's accommodating nature turns into a real nightmare.