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!