The story then flashes back to the married life of Sao and Thi, who, despite some hardships, live happily in a thatched hut perched on stilts; when the water level rises, they relocate to a boathouse. As they adjust to the realities of having no land to till or to raise livestock on, their daily routines of fishing, cultivating potted veggies and collecting rain water in jars feel less futuristic than primeval, as if they were rescued animals on Noah’s ark. Debussy’s “Claire de lune” forms a soundscape for the stormy weather, adding a touch of modernist lyricism, though the music comes to sound incongruous and passe in the sci-fi-heavy coda.