Under Their Skin

In this unpredictable thriller, 12-year-old twins investigate their new stepsiblings, only to discover that their entire world may be based on lies. Nick and Eryn are shocked to learn that their new stepfather has children (ones that neither he nor their own mother have ever mentioned), and they are downright baffled at their parents’ insistence that the two sets of siblings never meet. Nick and Eryn take up the challenge to find out just what’s going on, but the truth leads to bizarre revelations with far-reaching ramifications. Haddix (the Missing series) starts off conventionally, presenting the twins’ situation as a family drama with elements of mystery, before gradually peeling away the layers to show a deeper, disturbing story that explores what it means to be human. Nick and Eryn are appealing, believable protagonists, though the supporting characters (particularly stepsiblings Ava and Jackson) aren’t as fleshed out. Haddix’s worldbuilding is solid, though, and her premise intriguing, raising many more questions than it answers while leaving the story open for further exploration. Ages 8–12. Agent: Tracey Adams, Adams Literary. (Jan.)