Base Camp (4)
Since it's narrated by a twelve-year-old and a fourteen-year-old, the language in The Red Pyramid isn't too hard to understand. The concepts, however, can get a bit mind-bendy. Get used to the ideas that mortals can host ancient gods, that the realm of spirits and the dead can overlap with our world, and that an ancient and powerful cat goddess can get distracted by a wrecking ball. There are some crazy plot twists, too, which you might see coming if you keep your wits about you while reading.