High school senior Michael Siversten has never felt very powerful. He’s a high school senior with a scraggly beard. He has something called Asperger’s, which he researched relentlessly. He knows he says awkward things sometimes, and he needs a helper to get him through school—but he likes people, and people like Michael.

One night, he’s troubled by a dream in which his old assistant and mentor, Alexander Davidson, exclaims Michael will soon be “one and the same.” The vivid dream is a bit of a puzzle, so Michael seeks Alexander out. What he learns...