Whisper of Memory by Brinda Berry

Weapons training and winter formals… a deadly combination

All Mia ever wanted was to fit in at Whispering Woods High. But being a portal-finder who dates a guy from another dimension sort of makes it hard. Mia's brother disappeared over a year ago, and now agents from the IIA are policing people’s movements through dimensions. She’d trusted Dr. Bleeker from the local university when he’d told her the IIA were the bad guys. But even a girl with an extraordinary ability to sense things can make...