Heiress Rachel Argyll is murdered at her family estate. Eighteen months later, as her widower prepares to marry again, the identity of the murderer is thrown in doubt.
The morning after Leo and Gwenda's party, Arthur tries to return to Sunny Point in an effort to clear Jack's name, but receives very little support from the Argyll family, who have Mickey unceremoniously escort him off the premises. Left with no option but to reveal everything he knows, he provides irrefutable proof that Jack is innocent. His revelation has devastating consequences for the members of the Argyll family, who begin to realise that if Jack did not kill Rachel, one of them must have.
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.