It was said that if you write to the Bridegroom's Oak, the love of your life will answer back. Now, the tree is giving up its secrets at last. In 1940s Germany, Sophie is excited to discover a message waiting for her in the Bridegroom's Oak from a mysterious suitor. Meanwhile, her best friend, Hanna, is sending messages too--but not to find love. As World War II unfolds in their small town of Kleinwald, the oak may hold the key to resistance against the Nazis. In 1980s West Germany, American teen transplant Jenny feels suffocated by her strict parents and is struggling to fit in. Until she finds herself falling for Lena, a punk-rock girl hell-bent on tearing down the wall separating West Germany from East Germany, and meeting Frau Hermann, a kind old lady with secrets of her own. In Spring 2020, New York City, best friends Miles and Chloe are slogging through the last few months of senior year when an unexpected package from Chloe's grandmother leads them to investigate a cold case about two unidentified teenagers who went missing under the Bridegroom's Oak eighty years ago.