It is 1554. King Henry VIII's two daughters hold England's future in their hands. Queen Mary is on the throne and preparing for her marriage, and has imprisoned her half-sister Princess Elizabeth in the Tower of London.
Into this dangerous mix of rivalry and politics hurtle twins Scarlet and Thomas, on their sixth time-travelling adventure. Thomas works with the executioner and meets the monarch, who is deciding which of her enemies should be executed. Meanwhile Scarlett sneaks into the tower and befriends the girl held there, the young princess. With the queen and her half-sister fighting for power, and the executioner sharpening his axe, who will be the first to kneel on the block? Will the twins keep their wits about them - or will they lose their heads?