Arthur and Gwen married young. Twenty years on, Gwen's got it all: wealth, beauty, a famous husband who's the founder of Britain's most successful tech company, stables full of horses, millions of followers on Instagram, an unstable lover, a wayward son, a hoard of secrets, an aching heart, and a cyberstalking blackmailer who calls himself The Invisible Knight. As the Wiltshire town of Abury prepares to celebrate the fortieth birthday of its favourite...