The Amber Shadows, by Lucy Ribchester, begins in the cold winter of 1942 at Bletchley Park, the site for British codebreakers during World War II. Honey Deschamps, who transcribes coded messages, meets a man while walking home in the dark who gives her a package with Russian postal marks. Inside is a small amber block, mysteriously engraved with Cyrillic characters. Is the amber from her Russian father, or a tricky test of loyalty from her Bletchley superiors? A romance with the man who gave her the package is a heady secret for Honey, but after being watched and reported upon, and witnessing strange events and a friend’s disappearance, she realizes that Bletchley is a dangerous place to be. This novel’s historical details and twisty suspense make it a vintage pleasure.