Wing and Claw #2: Cavern of Secrets by Linda Sue Park

My name is Raffa, and animals are being trained to attack Afters living in the slums. My uncle is the one who discovered how to create mixtures using the red vines, and he believes he's doing something good. I don't know if he realizes his creation is being used to attack humans. I've created a mixture to counteract the effects on animals, but I don't know how to get it into them. The Chancellor has guards searching for me everywhere. I've discovered my parents' home burned to the ground, and don't know if they're alive or dead. Trixin doesn't want to get involved, but her brother Jimble and his friends have proven to be a tremendous help. He's willing to do whatever I need of him, but Trixin will kill me if he gets into serious trouble. The animals must be cured and freed tonight, or it may be too late.

You should read the first book in the series to fully understand the red vine, and Raffa's history with the problem. I've enjoyed how Raffa and Kuma have worked together, although Raffa spent the second half of the book alone. Characters helped him, but he was mostly independent. An entertaining aspect of the story is his relationship with a bat named Echo. The red vine enables Echo to speak in very short phrases, and he mostly acts as Raffa's lookout. He's very innocent and communicates literally. This creates some miscommunication, since Raffa isn't always able to foresee things from the bat's viewpoint. The plot doesn't have a great deal of action, although it has its moments. The most engaging part of the book is found in the conflict. Most readers will probably have an issue with experiments being performed on innocent animals, and Raffa even has second thoughts about the effects on his friend Echo. The series continues in the sequel Beast of Stone.