C610 The Mystery of the Secret Room

Sikou Nianxi gently stroked the polished iron chain. Was the black color her father's blood?

If the blood would come out from the friction, it meant that it would go through a violent struggle. The thick iron chain clearly knew that struggling was useless, so why did it still struggle?

Could it be that this struggle was actually not to escape, but to something in this room? Then what was it