We Do Not Welcome Our Ten-Year-Old Overlord

All Kim wants to do is play Dungeons & Dragons with his friends and ride his bike around the local lake. But he has always lived in the shadow of his younger sister. Eila is a prodigy, and everyone talks about how smart she is, though in Kim's eyes, she has no common sense. So when Eila finds an enigmatic, otherworldly globe which gives her astonishing powers, Kim not only has to save his sister from herself, he might also have to save the world from his sister!