The Spy with the Red Balloon (The Balloonmakers)
Ilse and Wolf Klein have a secret: their blood is magical. They are accustomed to keeping secrets, which makes it slightly easier for them when they are forced into service during WWII. Wolf is sent to Germany as part of a mission to sabotage Hitler’s atomic bomb program. Ilse, the more gifted of the two, is sent to Oak Ridge, Tennessee to discover a way to use magic to deliver an atomic bomb being developed in the US.
The siblings’ missions become more difficult when Wolf’s plane is shot down—his Jewish identity putting him in even greater danger—and when Ilse is accused of treason after secret documents go missing from her laboratory. Ilse discovers a spy in Oak Ridge, who endangers her mission as well as Wolf’s. It is up to Ilse to unmask the spy and save both herself and her brother.
Told in alternating chapters from Ilse and Wolf’s points of view, this story is a sequel to Locke’s award-winning The Girl with the Red Balloon. Although it’s filled with diverse characters—gay, Jewish, and African-American—they feel one-dimensional. The magical system is difficult to understand, perhaps in part because the characters themselves don’t understand it, which makes the plausibility of the US Armed Forces putting inexperienced teenagers in charge of two vital elements of the war effort difficult to believe. Still, the story is fast-paced and may appeal to readers from middle school age to high school, especially those who were fans of the first book.