A domineering mother moves from a small town to the suburbs of a city with her daughter and son-in-law, yet soon grows restless with her new life. When she strikes up a friendship with the mysterious Scilla, her world suddenly seems rich with potential and before long, the pair are planning to open an art gallery together.

After a series of afternoons spent over coffee granitas in local bars, however, it quickly becomes apparent that there is more to Scilla than meets the eye.

Class, in all its manifestations and aspirations, is at the heart of Sagittarius, as misplaced confidence and ambition gone awry leads inexorably towards the downfall of a family.