Archie Dent is convinced that he and his friends Hachi and Fergus are the first three members of a new League of Seven: a group of heroes who come together to fight the Mangleborn whenever the monsters arise to destroy humanity. His belief is put to the test when they are forced to undertake separate missions.
In an alternate 1875 America electricity is forbidden, Native Americans and Yankees are united and eldritch evil lurks in the shadows. Young Archie Dent knows there really are monsters in the world. Trapped in underground prisons for a thousand years, the giant monsters have been all but forgotten until his parents and the rest of the Septemberists are brainwashed by one of the evil creatures, Archie must assemble a team of seven young heroes to save the world.
A stranger informs Simon that he is a Storm Maker --- part of a clandestine group of people entrusted with controlling and taming the weather --- and that he is in great danger. Soon Simon and his twin Ruby must race against the clock as they try to master Simon's powers in time to stop a rogue Storm Maker's treacherous --- and potentially deadly --- plans.