Shadow magic? Mike followed Harriet and looked around, but there was no sigh of his friend. When she stopped, Mike almost bumped into her. He wasn't sure what kind of shadow magic existed or who could use it. Again he realised he knew very little of all of this. 
He took his phone when Harriet asked and called again. Nothing. 
"It goes to voicemail after ringing a few times. His phone is on, but he doesn't pick up." He lowered the device. "Can you detect what kind of shadow magic happened?"