The Girl in the Wind - Iron on Iron, #2

The price for the truth might be their family. When Theo and Auggie return home-safe and sound and miraculously alive after being dragged into a murder investigation-all Theo wants is for life to get back to normal. No more murders. No more investigations. Nothing, in other words, that might put Auggie in danger. But when a girl from school goes missing, Theo finds himself reluctantly drawn into looking for her.
Shaniyah was his former student, for one reason. And, for another, no one else seems interested in where she's gone. Worse, her disappearance seems to be linked to a break-in at Theo and Auggie's house. The search, though, quickly becomes more complicated than either Theo or Auggie could have expected. Shaniyah, they discover, had been conducting an investigation of her own, looking for another missing student.
And the path to learning the truth about both disappearances, Theo fears, leads back to the Cottonmouth Club.