Road 13 and Kalos Power Plant | Walkthrough Pokemon X/Y Guide

Head north-west. In Your equipment, use Dowsing Machine (obtained en route to Cyllage). Follow the direction the rod (machine) points to find a Power Plant Pass. Then, head north-west further for a single door, and enter the Power Plant. On the right there are the hostages, You can't help them now. Go left and proceed clock-wise defeating all of the Team Flare Grunts. Once finished, talk to the hostages and head back to Road 13. Once there, head south-east. Back to Luminose city.