Josie O’Malley does a lot to help out Mam after her father goes off to fight the Nazis. She wishes she could do more—like all those caped heroes who now seem to have disappeared. Josie can’t fly and control weather like her idol, Zenobia.  But perhaps she can put her math smarts to use cracking puzzles for the government.

When an official tosses out her puzzler test because she’s a girl. Therefore it soon becomes clear that an even more top-secret agency has its eye on Josie. Similarly with two other applicants: Akiko and Mae. The trio bonds over their shared love of female superhero celebrities, from Hauntima to Zenobia to Hopscotch.

But during one extraordinary afternoon, they find themselves transformed into the newest (and youngest!) superheroes in town. As the girls’ abilities slowly begin to emerge, they learn that their skills will be crucial. Their skills could thwart a shapeshifting henchman of Hitler. Just maybe, in solving an even larger mystery about the superheroes who’ve recently gone missing.

Inspired by remarkable real-life women from World War II—the human computers and earliest programmers called “the ENIAC Six”—this pulse-pounding adventure features bold action and brave thinking, with forty-eight pages of comic book style graphic panels throughout the book. Readers will want to don their own capes for an adventure, and realize they have the power to be a superhero, too!