Submitted by Spectre
Jospehine Leonides (Honor Kneafsey), the young daughter of Magda (Gillian Anderson) committed both murders. She hated her grandfather for his cruel nature towards her and his attempts to snuff her dreams of being a ballet dancer. So she poisoned him and framed his young widow Brenda (Christina Hendricks) for the crime. She then proceeded to fake her own attempted murder and kill her Nanny when she began to suspect Josephine.
Lady Edith (Glenn Close) discovers the truth. Terminally ill with no hope of a cure, she decides to take the blame for both murders, not only to clear the innocent Brenda, but to spare Josephine a life of institutions and public outrage.
Charles Hayward (Max Irons) and Sophia (Stefanie Martini) discover the horrible truth and attempt to pursue Edith and Josephine. As they race into a quarry, the realize Edith’s plan; to kill Josephine and herself in a murder-suicide, to protect the remaining family. Charles and Sophia can only watch as the car goes off a cliff, exploding into a ball of fire. Sophia sobs that her family corrupted her sister while Charles consoles her, telling her none of what happened was her fault.
The film ends with a shot of a painting of Aristide Leonides. It is left unclear if the truth of his murder will ever be truly revealed.