Grace Sachs (Nicole Kidman) lives her ideal life: Grace is a successful psychotherapist, has an excellent doctor husband and a son who attends an elite private school, and she is preparing to publish a book on gender issues, "You Should Have Known", which mainly rebukes women for not listening to their intuition and not seeing the meaning presented by their male partners. However, a few weeks before the publication, a fatal incident involved her husband who suddenly disappeared. Grace found that there was a huge crack in her life, and there were signs in the past, but she didn't listen to her intuition. After the incident was made a big deal, the heroine had to give up her current life for her son. Hugh Grant plays Jonathan Sachs, a well-received pediatric oncologist who gives the impression of a loyal husband and a good father, but in fact he had unusual signs before his disappearance. Noah Jupe plays Henry Sachs, the 12-year-old son of the male and female protagonists.