It's a well-understood trope for fatherless children to believe the absent parent is wonderful and special. In the case of these four young friends, it turns out to be fact, thanks to the parallel world of magic in this series.
Of course, 'the magical academy' is a popular theme as well, and this one gives Hogwarts a run for its money.
When the evil in a world is clearly labeled as such, that is also reassuring. These four friends are precisely the same age, even sharing their birthday, and begin the tale at the age of eleven. I'm hoping that as they get older, their perspective on the complexity of their magic universe is also given more dimension. But for now, the reason grownups are allowing them to be so close to dangers such as the Spell of Whirldungen is safely a product of mass hypnosis.
That universe is very engrossing and well-conceived. There are plenty of loose ends to sustain the coming volumes, but they have ended this first one with a satisfying triumph.
Spoiler: the being depicted on the cover is NOT a Whirldungen, merely a dragon. Vaguely disappointed by that. :)