Girl. Boy. Sea.

A British boy survives the sinking of his yacht in a huge storm off the coast of Morocco. After days alone at sea in a rowing boat Bill rescues a girl clinging for her life to a barrel. Aya was escaping to Europe when her migrant ship was destroyed in the same storm. When they land on a desert island, they're surprised to be confronted by a stranger who is not what he seems... and back out on the waves once more in the dark deep, a shadow follows...