A decade ago, the Guardians of Childhood, magical beings that protect the lives and virtues of children, recovered from the brink of ruin and drove Pitch Black back into the shadows where he belonged. But the Boogeyman is never content with hiding under beds, and would not accept defeat; he's coming back with a vengeance, and he's rallied others around him, others like him who embody the dark things in the world.
This time, it is the Guardians versus the Anti-Guardians. Powerful new beings are being chosen by the Man in the Moon on one side and the Nightmare King on the other. Magic sparks are flying on a colossal level, and some humans are being born with or granted magic of their own that is linked to these concepts.
The Earth will never be the same again, and war is brewing. Both sides aren't just fighting for the belief of children this time; they have to tap into the beliefs of adults across the world if they want to tip the balance. With the darker side of human nature already clashing so dramatically with the light side, nobody can say who will prevail.