Book 5 in the Christie and Agatha's Detective Agency series!‘Einstein will be all ready to deliver his oh-so-important speech … only to find that he doesn’t have the equipment to deliver it with!’Christie dreams of a train adventure – the kind she’s read about in fiction. But Christie and Agatha’s journey aboard the Green Express, with company including Albert Einstein, is more than even they bargained for. The twins uncover a plot to sabotage the physicist’s radio broadcast, and it’s all up to them to thwart it before their journey ends. About the Christie and Agatha's Detective Agency series:It’s not easy growing up in the 1920s. While Christie can usually be found up a tree or trying a spot of amateur engineering, her shy twin Agatha buries her nose in books and dreams of being a writer. The pair couldn’t be more different. But when a scientific discovery goes missing, they find that together they make a winning combination and Christie and Agatha’s Detective Agency is born. Join the twin detectives as they solve thrilling mysteries all over the world!