Coming to Terms with the Dead

It's summer, on the beach of this little town in Brittany, a man around 40 is building a sand castle. A few people watch him. We will be told the story of three of them : a boy, Jumbo, aged 9 ; Francois, aged 30, and his sister Zaza, around 40. All of them had to deal with the death of somebody they cherished. How to keep on living after this?