Tracking.

Bo Qingtan returned to Ding Shu's house and asked, "Old man, hand us something your daughter-in-law used frequently." 

Ding Shu was surprised but knew that since the immortal master had asked for it. The matter was important. He rushed inside the room where her daughter-in-law stayed and picked up a dress and a hair comb from the dresser. 

He asked, "Exalted Immortal, will this work?" 

Bo Qingtan gazed at the hair comb, found a few strands entangled with it, and nodded. He took the hair comb carefully and left without another word. He was not interested in conversing or consoling this old man. Bo Qingtan regrouped with Shi Lang and found that Yun Xue had finished carving a circle on the ground and made a few seals with her hands.

Shi Lang said, "When she waves at you, toss the comb inside the circle. Make sure to time your action perfectly. This will increase the accuracy of the tracking."