In this acclaimed historical adventure, Newbery Honor–winning author Adam Gidwitz introduces readers to Max Bretzfeld, an eleven-year-old Jewish boy sent from Nazi Germany to London via the Kindertransport. Determined to reunite with his parents, Max devises a daring plan: become a British spy and return to Berlin.

Max's journey is anything but ordinary. Accompanied by two supernatural beings—a dybbuk named Stein and a kobold named Berg—who perch invisibly on his shoulders, Max navigates the challenges of a new school, faces antisemitism, and undergoes rigorous spy training. His mechanical genius, particularly with radios, catches the attention of British intelligence, setting the stage for a high-stakes mission.

Blending elements of Jewish folklore with the stark realities of World War II, Gidwitz crafts a narrative that is both fantastical and grounded. The story offers a nuanced exploration of identity, courage, and the complexities of war, all while maintaining a tone accessible to middle-grade readers.