The Lightning Thief looks at two co-existing worlds: the mortal world (the world as we know it) and the immortal world (the world of the gods). Our narrator learns that there are different versions of reality in the world, and that "reality" is just the way people choose to interpret a situation. When Zeus's lightning bolt strikes a bus, the mortal world understands it as an explosion due to mechanical failure and nothing more, while the immortal world interprets the bolt as a sign of Zeus's wrath. People choose what they want to see. Our narrator straddles both the immortal and mortal worlds, and he, therefore, learns how to exist in a world of various realities.