Sometimes I honestly don't know why I continue to read the Magic Tree House books. I'm not sure what the difference is between the the normal books and this 'super adventure' It wasn't a Merlin Mission because Merlin wasn't the reason for the journey, but could it be placed in the original 28 book series? The only problem is that Jack and Annie didn't get to know Merlin until the Merlin Missions. Anyway, this was your normal-type Magic Tree House book. I had a slight problem reading it because I know a little bit too much about WWII so Jack and Annie's carelessness (that would've gotten them arrested by the Nazis in real life), and the easily crackable code that they used, along with Teddy and Kathleen bothered me a bit. A good story for younger kids.