My absolute favorite book in 4th grade. I must have checked it out from the library at least fifteen times, and the result of this is that I still remember the plot of the story almost perfectly.
Eleven-year-old Naya Nuki and her friend Sacajawea (10-year-old Madeline: OMG LIKE THE REAL PERSON!) get kidnapped by an enemy tribe and sold into slavery. Naya decides that's not cool, and after her friend gets sold to French traders she starts making plans to blow that popsicle stand and find her tribe again. She steals supplies, hides them, and waits for a stormy night so she can get away without being tracked. Over the course of her journey she kills stuff, evades enemy scouts, escapes a bear attack, cures herself when she gets sick...I could go on. Honestly, there is not one thing this girl does that isn't unbelievably badass.
I sort of worshipped this book as a kid. In case that wasn't clear.