North felt his pulse kick up. “We’ll wait.”

Gwendolyn whisked out from behind the counter and disappeared into a back room. North heard a door open and close. He knew Swan was on her way down into her basement.

Sierra looked at him. “Are you thinking the same thing I’m thinking?”

“My father knew or suspected that someone was following him,” North said. “He bought two artifacts—the one he took with him was a decoy. The other one he left here at the shop until he thought it was safe to come back for it.”

“Yes,” Sierra said. “That sounds logical.”

The door in the back room opened and closed again. Gwendolyn Swan appeared. She had a black metal rod in her hand. It was about a foot long.

“Don’t ask me what this is,” she said. “I suspect it was part of a machine or a tool. I asked your father why he wanted it. He said he thought you might find it interesting. Something about you having an engineer’s mind.”

She handed the rod to North. The instant his fingers closed around it he felt a familiar rush of recognition. He tightened his grip on it.

“Yes,” he said. “I am interested in it.”

Gwendolyn eyed him. “Any idea what it is?”

“You’re right. It was probably part of an old lab machine. I find vintage engineering artifacts very intriguing. I collect them.”

“It’s all yours,” Gwendolyn said.

“Is there anything else you want to tell me?” North asked.

“Nope. Now, if we’re done here, I’ve got work to do.”

Sierra smiled at Gwendolyn. “I do have one more question.”

Gwendolyn tipped her head slightly. “Yes?”

“The crate of artifacts that you bought, the one that contained the radio and the metal rod, I assume it was delivered by a go-between?”

“Matt Harper,” Gwendolyn said. “One of my regulars.”

“Thanks,” Sierra said. “By the way, I got your message. When I finish this job I will be glad to authenticate your artifact.”

“Right,” Gwendolyn said. “Thanks.”

Sierra glanced at North. “We can go now.”

He was still trying to process the information she had extracted from Swan. Now they had a name. Matt Harper.

“All right,” he said.

She led the way out of the shop. North waited until they were well clear of the door before he spoke again.

“I had a few more questions,” he said.

“I think Gwendolyn Swan told you the truth. She doesn’t know anything else that would be useful. Our best bet now is Matt Harper.”

“The go-between who transported the crate that contained the rod and the radio?”

“Right. I’ll contact him. He may not know anything helpful but I think he’ll talk to us—or, at least, to me.”

“Why?”

“Matt owes me,” Sierra said. “Among go-betweens, repaying favors is not just good karma, it’s essential for staying in business. What the heck is that metal rod?”

“I have no idea,” North said. “But I do know one thing for certain.”