Edith Darling and Thomasin Shaw are presumed dead. Without Worthing and the police breathing down their necks, they have their freedom, and most importantly, they have each other. But without Excalibur to chase, Edith finds herself haunted by the mistakes she made along the quest, and Thomasin wonders if she has what it takes to not be a criminal. When Edith's sister, Marigold, learns of their survival, she demands a meeting in London. Only as soon as they arrive, Edith and Thomasin are ambushed by a mysterious organization that claims to protect lost, magical artifacts. They want Edith and Thomasin to join their search for the Holy Grail, but first, the two women must prove themselves by acquiring Galahad's Shield, without which they will not be able to reach the Grail. From Glastonbury to France to the fabled island of Corbenic, Edith and Thomasin must make their way through treacherous grounds filled with mystical riddles and trials to ensure their survival. This new quest offers Edith purpose and Thomasin redemption, but with all their hopes set on finding the Holy Grail, they'll both have to decide what matters most-their love or the quest.