The League of Seven
When an alternate 1875 steam-driven America rediscovers electricity, the lifeblood of the Mangleborn monsters, and the secret society to protect humanity from the Mangleborn is compromised, twelve-year-old Archie must assemble a team of seven young heroes to save the world.

When an alternate 1875 steam-driven America rediscovers electricity, the Mangleborn monsters, and the secret society to protect humanity from them and 12-year-old Archie must assemble a team of seven young heroes. The plot contains violence.
Science fiction, Juvenile fiction, Adventure stories, Adventure and adventurers, Secret societies
Alan Gratz, Brett Helquist
Alan Gratz has wanted to be a writer ever since he was a kid. He went to the University of Tennessee to study creative writing, and ten years and more than sixty-five rejections later he was finally able to get his very first book published. Now Alan is the author of fifteen books for young readers, many of which have won state awards, appeared on the New York Times bestseller list, and been voted their favorite book of the year by students and librarians.
([source][1])

Photo by Wes Stitt


  [1]: https://www.alangratz.com/about/