When you live in a volcano, ride to school in a helicopter, and regularly see your dad on the news with the caption "EVIL GENIUS" underneath his picture, it takes a lot to rattle you.
Until you get a message that says: We have your father. Deliver the NOVA in 24 hours or we will kill him.
What's a NOVA, you ask? It's a nuclear bomb capable of turning the city into a radioactive mushroom cloud, and ever since Fiona's dad built it, it's caused nothing but grief. But telling him to stop building weapons is like telling Michelangelo to stop painting. And that's why thirteen-year-old Fiona has a flamethrower strapped to her arm.
After all, who'd mess with a girl who can throw fireballs?
Apparently, these guys.
Big mistake.