Earth needed help - and nobody else was going to step up
Graciela Juarez has gone from a late-twenties college student to Second Order Guardian and one of the Empire's better pilots. But events on Earth are building to a climax, and the Empire is determined to let Earth sort things out for itself - or not. It really doesn't matter to them.
But it matters to Grace. By whatever means necessary, she will save Earth from the demons - and from its own insanity.