Set on a small, blustery fishing island off the coast of France, Coastliners is the story of Mado, a young woman who returns to her childhood home to find the local community torn apart by family feuds, bad tides and murky political machinations. Passionate, stubborn Mado tries to save the livelihoods of the villagers of Les Salants by urging them to work together to save the beach from erosion, both natural and man-made. The villagers eventually cooperate with the help of Flynn, a charismatic stranger with a shady past. Then there's her father, taciturn Grosjean, as "prickly and tightly layered as an artichoke", and local, wealthy businessman Brismand who also seems to be hiding something. Mado must unravel these mysteries, while attempting to keep a hold on her own sense of self in this claustrophobic, close community.