While recuperating on the south coast of France after a terrible accident, 13-year-old Beau meets Lelee, a sort of wild child, more at home in the sea than on land.

Together with Beau's younger sister they roam around the Bay of Angels in their little boat in search of a box that Lelee believes contains a fortune.

They are constantly being watched by a group of smugglers who are looking for the same box.

The summer turns into an intriguing adventure which gradually unfolds as Beau regains his strength, thanks to his new surroundings and the people he meets, including his eccentric aunt, her companion Clothilde and, above, all, Lelee, who also has her own sad tale that means she must one day leave the place she loves.