wards vs tracking

He hesitated in midpoke. "You're leaving?"
"It's safe," I said. "I've got measures in place here that will prevent Grevane from finding you by magical means."
"You mean with a spell or something?"
"Yeah," I said. "My spells should counter Grevane's and keep him from locating you while I get some things done."
"You won't be here?" Butters said. He didn't sound too steady.
"Grevane won't find you," I said.
"But what if he does it anyway?"
"He won't."
"Sure, sure, he won't. I believe you." Butters swallowed. "But what if he does?"
I tried to give him a reassuring smile. "There are more wards in place to stop someone from coming in. Mouse will keep an eye on you, and I'll leave a note for Thomas and ask him to stay home tonight, just in case."


Dead Beat Chapter 7, Page 62