Here, There Be Dragons by James A. Owen
John, Charles, and Jack never knew another world existed besides their own, England during World War I. They find out that there is, and that they have to keep the atlas to it safe pretty quick when they find themselves being chased by a pack of Wendigo. And they don’t even know what Wendigo are, just that they better follow a peculiar man named Bert to safety to avoid being killed by them. They soon find themselves in the Archipelago of Dreams, where every tale they’ve ever been told is real, and they’re caught in the middle of a dark battle for control over the Archipelago.
The first thing that hooked me with this book was the title: Here, There Be Dragons. I’ll admit that I don’t know much about maps and sailing, but I do know that the phrase “Here, there be dragons” is a phrase used by early mapmakers to indicate that they have no idea what’s beyond the edge of their map, as it’s uncharted territory.