Under The Nightingale's Wings

Fern's parents send her to live with her aunt and uncle for the summer in Colorado. She gets a job, and befriends two kids that live in the same apartment building as her aunt, soon to find out they aren't exactly people she wants to be friends with. But before she can tell them, the two drag her into a dilemma, involving the abandoned building next to their apartment complex. There, the three run into something they would have never expected, and they leave Fern behind to take the fall.