Christophe Perrin, a renowned oyster farmer in Arcachon Bay, is the victim of a murder attempt. His three daughters rush to his bedside, where he lies wounded and unable to manage L'Héritage, the family oyster farm. Nathalie, the eldest, wants to sell the farm, and Marianne, the second, agrees. But quite unexpectedly Tessa, the youngest, refuses and decides to run the farm herself. With no experience, she will have to prove her ability to do so. At the same time, since the police inquiry appears to be going nowhere the three sisters decide to lead their own investigation. Little do they suspect that their discoveries could tear the family apart.