Erin Alexander and the Celestial Archer

Erin lives a normal, happy life in an out-of-the-way, productive town. One day, a ghastly beast appears on the screen of her brand-new Kindle, and what follows is the chaotic adventure of 9 kids and a school of children who have been chosen by gods and goddesses to help prevent the world's disasters. Of course, the school is run by a guy called Dave.