Oh No! Not Again! (or How I Built A Time Machine to save History) (or at Least My History Grade) by Mac Barnett.
How’s THAT for a mouthful of a title? Honestly, the plot is hardly less confusing. I rather enjoyed this book and my son did too, though I suspect he missed what was really happening in the story.
The main character (hardly a heroine) is miffed for having gotten one question wrong on her history test. Rather than just accept it, she uses her genius to build a time machine and change the past to fit her answer. The question was about which country has the earliest known cave paintings. Her wrong answer was “Belgium”. So, with a little trial and error—it is a homemade time machine after all—she finds herself in prehistoric Belgium. Armed with paints and brushes, she proceeds to paint a fantastic cave mural, since the inhabitants of the cave seem disinclined to do it themselves. However, while she is busy drawing robots on the cave wall, the cavemen discover her time machine and proceed to bring all manner of people from all points in history back to the prehistoric era.
Needless to say, history becomes a little more changed than she anticipated. One the bright side, she got that one question right on her test! On the other hand, all the rest of her questions were wrong due to her effect on history. Like I said, the finer plot points are lost on my son, but the book is funny and entertaining nevertheless.