When Gabby Duran is recruited to babysit aliens secretly residing in her hometown, the unapologetically bold tween receives an Intergalactic Babysitter Orientation Guide from her school principal, who also happens to be an extra-terrestrial. Though not a by-the-book kind of girl, Gabby refers to this information-packed guide for what she needs to know to successfully babysit kids from another planet, including a dossier of potential clients, a rundown of otherworldly gadget, and tips and tricks for dealing with her unusual charges. As the best babysitter in the galaxy, Gabby even shares a few tricks of her own!