A Dark Spirit Breaks Into School

It's about these 3 kids, Daniel, Sierra, and Jake go on an adventure when they just found out that the 3 of them that they're a part of a world with monsters, gods, and evil beings. Will they be able to stop Dragolion before he destroys the 9 worlds forever? Read to find out.
Inspired by Greek, Roman, Norse, Egyptian, and Rick Riordan who created the PJO Series, the HOO Series, the Kane Chronicles, and Magnus Chase and the Gods of Asgard Series.