“Following Georg Hoffman’s revelation that he may have found The Missing Sister, Maia and Ally discover that all they have to go on is an address of a vineyard in New Zealand, plus a drawing of an unusual star-shaped emerald ring. Deciding that CeCe, who lives in Australia, is the closest, they send her to investigate with her partner, Chrissie. So begins a race against time to identify the Missing Sister, so she can join her sisters on The Titan to lay a wreath at a spot on the Aegean Sea where Ally last saw Pa Salt’s boat. It’s a race that takes them across the globe, as Mary McDougal, the woman who has the emerald ring that can confirm for certain if her daughter, Mary-Kate, is the Missing Sister, has embarked on a world tour after the death of her husband.”