1 July 1969. The Investiture of the new Prince of Wales. When Arianwen Hughes is arrested driving with a home-made bomb near Caernarfon Castle, her case seems hopeless. Her brother Caradog, her husband Trevor, and their friend Dafydd are implicated in the plot, the evidence against them damning. Ben Schroeder's reputation as a barrister is riding high after the cases of Billy Cottage and Sir James Digby. But defending Arianwen will be his greatest challenge yet. Trevor may hold the only key to her defence, but he is nowhere to be found. . .