Ordeal by Innocence

Episode 3 (1x3)

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The Argyll children are forced to relive the events of the terrible Christmas Eve when Rachel was murdered to finally uncover the truth about who killed her and why. However, they soon discover that everyone in the family had a reason for wanting to get rid of her. Arthur's assertion that he is telling the truth puts his life in danger, prompting a race against time to save his life, while Leo and Gwenda's wedding descends into violence as a vengeful party plots to take the law into their own hands.