Episode 12 recap: Ruan Hei passed away without treatment.

Hu Ba Yi wants to go back to find the Qin Emperor's Bone Mirror. Xue Liyang asked him if he was being reckless, but Hu Ba Yi believed that their purpose in coming was to find the Qin Emperor's Bone Mirror. He couldn't just let something they were so close to obtaining slip away. Ignoring Xue Liyang's objections, he once again entered the cabin where the giant octopus was located. He covered himself with a canvas and slowly approached the Qin Emperor's Bone Mirror. However, just as he was about to put the mirror in his pocket, the giant octopus spotted him.

Hu Ba Yi was caught by the giant octopus, but Xue Liyang rescued him using a whaling harpoon. Just as they made it back to the yacht, the Mary Celeste caught fire and exploded. Xue Liyang realized that the reason why the seawater couldn't flood in where they were was because of the pressure created by the burning Yin fire. This revelation led Hu Ba Yi to understand the meaning behind the legend of "Yin fire emerges, spiral forms."

The group boarded a lifeboat and started heading back. Suddenly, they encountered a steep slope, causing the lifeboat to capsize. After struggling in the water, they finally managed to climb back onto the surface. When they found Ruan Hei and Duo Ling, they discovered that Duo Ling was crying uncontrollably, and that's when they learned that Ruan Hei had passed away.

Before his death, Ruan Hei once again requested Hu Ba Yi to ensure that Duo Ling is sent to France. He also revealed to Hu Ba Yi that he found Duo Ling in a ghost ship near the Spiral of Corals.

After Ruan Hei's passing, Hu Ba Yi placed the largest pearl into his mouth and decided to bury him according to the customs of the Sani people. However, they were surrounded by the sea, and Fatty jokingly suggested that Ming Shu carry Ruan Hei back. Naturally, Ming Shu refused. Hu Ba Yi examined the surrounding feng shui and felt that it was a suitable burial site.

In order to find a coffin for Ruan Hei, Hu Ba Yi and the others searched the area and unexpectedly discovered a large clamshell. Ming Shu informed them that the clamshell was called the "Clam Demon," a river clam that had become a spirit. People from the Hentian Department often used it to attract other river clams. Apart from the Clam Demon, they also found a large bronze tripod ear. Based on this, Hu Ba Yi concluded that this was the site of the Hentian Department. The disappearance of the Hentian Department was likely due to being involved in the Coral Spiral and then falling into this cave.

After the burial of Ruan Hei, the group continued to search for an exit but couldn't find one. Hu Ba Yi noticed a peculiar phenomenon—the place they were in was half hot and half cold. While resting, Ming Shu suddenly felt an icy sensation all over his body. When he opened his eyes, he realized that he was lying in seawater. He quickly woke everyone up, realizing that the tide was rising.

To avoid the incoming seawater, they climbed to higher ground and discovered a small path. However, the end of the path was blocked by rocks.