Horne’s fusion of superhero fantasy and YA SF follows a teenage vigilante with autism whose mission is to protect the inhabitants of his city from harm.

Advent 9 is the last of the “Powered” people in Hearth City doing the “hero thing,” as all the others have either retired or quietly disappeared. The teenage boy has impressive powers (including the ability to fly, incredible agility, and superstrength), but he isn’t a stereotypical superhero; he doesn’t know where he came from, instinctively seeks solitude, can’t seem to look people in the eyes, and is tormented by seemingly imaginary creatures he calls Hummingbirds, which follow him wherever he goes. He also has no fixed address and sleeps on rooftops in the city. Advent 9’s life is turned upside down when he clashes once again with Dr. Felix Antiworld, an infamous supervillain. Antiworld and Advent 9 have been battling for ages, but this time is different, as the villain has used a machine that can traverse the multiverse to find Trancedragon, who looks like Advent 9 and has all his powers. However, instead of an innate drive to help people, Trancedragon wants to destroy everyone and everything he sees. Antiworld’s plan is to have Advent 9 and Trancedragon kill each other, but it doesn’t quite go as expected, and soon, the villain is forced to team up with Advent 9 to save the world from annihilation. Trapped in the city’s catacombs, the two must work together in order to survive—and, in the process, they begin to understand each other on a much deeper level.

Two major strengths of this novel are its portrayal of Advent 9 and its exploration of his autism. Over the course of the story, Horne excels at cultivating the complex, tumultuous relationship between Advent 9 and Antiworld, and many readers will find a sequence at the end of the novel to be particularly affecting. The novel’s comic-book–style tenor is also noteworthy, as it’s audacious, fantastical, and, at times, hyperbolic: “He was immense. The towering shoulders, the square jaw, the enormous fists were barely visible—a black outline on a field of darkness. His cape was an endless conduit to the clouds, twisting like a whirlwind of black flames. The height, the calm, the overwhelming presence of this titan was more than he could’ve imagined.” Additionally, the humor is spot-on and beautifully complements the overall tone: “Welcome to my secret lair,” says Antiworld at one point, “the place where I hatch my evil plots, and sometimes make popcorn while I watch Jeopardy!”The flies in the ointment, though, are the lack of backstory and inconsistent world building. The past is barely referenced, and the realm of Hearth City, while full of intriguing neighborhoods and inhabitants—such as the Morgans, a group of piratic criminals who are much more than they seem—is left largely unexplored. Readers will be left wanting to know much more of this city and its history.

An action-packed, if somewhat underdeveloped, superhero tale with a memorable protagonist and archnemesis.