Borderland — Rhiannon Lassiter

First of a trilogy, about a group of teenagers who travel into a parallel world. In this new world, each finds a new role: Morgan's black clothes mark her out as a magic-maker, while Alex puts his interest in war games to use, with potentially deadly effect. Zoe, new to the group, has to find
her feet and try to stop the others causing havoc. The stories combine exciting plots with strong characterization and insights into the real concerns of this age group.