When Xiaofan opened her eyes, she looked troubled. “This is dangerous.” She put the marble down on the table and pulled her hands away.

The marble rolled across the desk, and I caught it as it dropped off the edge. “And you know this how?” Caldera said.

“It is for secrets,” Xiaofan said. “To hold power over others, as a threat.”

“How many owners did it have?” I said.

“Many. One of them was you. You want the ones before?”

“Please.”

“Then, three.” Xiaofan tapped three places on the desk. “Maybe others, but those are too long ago.” Xiaofan moved her hand up, tapped the first place. “The first owner was a woman. Not young. She was . . . I don’t know the word. She held power over others, and others held power over her.”

“Politician?” I said.

“That too.” Xiaofan looked worried. “She was . . . cruel. Very cruel. She worked in secrets, and used this for secrets, too. You should fear her, I think.”

That didn’t sound good. “The second is a boy,” Xiaofan said. “Young, afraid. He held it, but only for a little while. A few hours, maybe. He gave it up quickly, to the third.” Xiaofan tapped the last spot on the desk. “A man. Young, but proud. He only held it a few minutes, and he lost it in violence.” Xiaofan looked at me, and her eyes were troubled. “I think he died. I saw it falling from his hand, then nothing. What is this thing?”

“You already figured that out,” I said. “It holds information. Secrets.”

Xiaofan shook her head. “I don’t want them.”

“Can you identify any of the previous owners?” Caldera said.

“I’m sorry?”

“The people who held this thing,” Caldera said. “We need to know their names.”

“No names.”

“Faces, then? If you saw them, would you recognise them?”

“I . . . don’t know.”

“All right, how about if you come down to the station and we show you some pictures? You think you could identify the person?”

“Wait,” Xiaofan said. “You’re with the Council?”

“Yes, I’m with the Council.”

Xiaofan shook her head quickly. “No. I’m sorry.”

“It won’t take long,” Caldera said. “Just an hour or two.”

“I’m sorry. No.”

“This is an important investigation. You just told us there was some sort of violence with this thing, and we need to find out what it was. You don’t need to worry, we’ll keep you safe.”

“I don’t want to go with the Council.”

“You might not have a choice if you keep refusing to help.”

Xiaofan looked alarmed. She looked at me, appealing.

“Okay,” I said, and got up. “I think we’ve got all we need. Thanks for the help, we really appreciate it.”

Caldera looked up at me in annoyance. “We’re not done.”

“Yes, we are.” I met her gaze and held it. “I think we should go.”

Anger flashed up in Caldera’s eyes, but I didn’t look away. We stared at each other for a second, tense, then Caldera rose with an abrupt motion and walked out. I shot Xiaofan an apologetic glance. “Sorry.”