1923: Evangeline English and sister Lizzie head for China's ancient Silk Road city of Kashgar. Lizzie is on fire with her religious calling, but Eva has her green bicycle and a commission to write a lady cyclist's guide. Present-day London: A young woman finds a man sleeping outside her door and gives him a blanket and pillow. And when she inherits the contents of an unknown woman's apartment, the two embark on an unexpected journey together.