What?? You haven't read Las sombras by A.C. Quintero yet?? You and your students (level 3+) are going to LOVE this book. It doesn't mess around, and your jaw will be on the floor within the first couple pages. Quintero is a MASTER of hooking and teasing the reader. Just when you think everything is about to be resolved, everything gets more complicated than you could imagine! Don't worry, it's not all mystery and crazy twists and turns, she also has humor and great character development. She has a way of writing material that is so believable, it sounds so natural and every day, but she manages to do it with a relatively limited vocabulary range, keeping it comprehensible for Spanish language learners AND in such a way that you never see the wild twists coming.
This is part of a series, but this book works perfectly as a stand-alone book. I'm praying that she has a sequel in her for this one, because let's just say the ending is the kind that will have you *dying* to talk to someone else who read it too because you. JUST. CAN'T. OMG!