Episode 4 recap: The Nian beast chased Sheng, Dan, Jing, Mo, and Chou.
Chun Yu discovered a secret on the door. She found that each door had a character that matched the one on her token. So she exchanged tokens with Gao Xuan. As she took the token, the Nian beast lunged at her, but the token was inserted into the door, causing the Nian beast to instantly disappear and the door to open. Everyone escaped from the hall, and then the door was locked. Qiang and Qing You argued over who should take credit for the pigeon, but Lao Lin said it was the result of everyone's unity and cooperation.
They walked around and found themselves back in the hall. They tried to return through the door, but it was locked again. Gao Xuan voluntarily exchanged tokens with Chun Yu. Chun Yu approached Lao Lin and asked him why he pretended not to know her during the day. He said he was worried about scaring her. At that moment, the Nian beast appeared again, chasing Chun Yu. Now that everyone knew the rules, they each found the corresponding door on their tokens. The Nian beast disappeared once again, and they continued to move forward. They realized that a new round of rotation would begin, and they needed to complete all the characters (Sheng, Dan, Jing, Mo, and Chou) before they could receive new information. They quickly found the doors corresponding to their tokens, and as soon as the broadcast was made, they inserted their tokens into the corresponding doorplates. After several attempts, everyone easily coped with the challenges and overcame their initial fear.
The characters Sheng, Dan, Jing, Mo, and Chou had all finished. They thought it was over, but to their surprise, they found themselves back in the hall, once again searching for their doorplates. Zhang Tian Qiang didn't want to run anymore in the previous rounds, so he exchanged his blank token with Lao Lin. The Nian beast reappeared, but the trumpet didn't sound. They thought Zhang Tian Qiang would rest in this round, but unexpectedly, the Nian beast chased the blank token. Everyone inserted their tokens into the doors simultaneously but got no response.
Zhang Tian Qiang was exhausted and unable to run. A Yong voluntarily exchanged tokens with him. While running, Zhang Tian Qiang was injured and collided with an iron pillar. Zhang Tian Qiang was torn between whether he should have exchanged tokens with A Yong when the blank token disappeared and reappeared on A Yong. The Nian beast instantly swallowed A Yong.
A Yong died, and the blank token appeared on Zhang Tian Qiang. Gao Xuan quickly snatched the blank token and, in the process of escaping, joined forces with Chun Yu to exchange tokens. The Nian beast kept running back and forth. Chun Yu took the opportunity to jump onto the Nian beast and discovered a secret. It turned out that there was a token slot on the bell the Nian beast wore around its neck. Gao Xuan took the opportunity to insert the blank token.
Zhang Tian Qiang, filled with sadness, smashed the Nian beast with a stool, causing it to disappear, but there was no trace of A Yong. The broadcast announced that they had successfully cleared the level.
While Chun Yu and the others were on the 19th floor, everything that happened was being observed by a man who leisurely sipped red wine while watching a large screen.
At that moment, Gao Xuan woke up, and the man sent him a message in response, saying that there were already artificial intelligence companies in China, and brain-computer interface technology was already very advanced. Chun Yu and Qing You woke up at the same time, hearing Zhang Tian Qiang shouting for A Yong. They hurriedly rushed over, and A Yong was being desperately rescued. The three of them anxiously waited outside the room.
Qing You was worried that A Yong wouldn't wake up, but the doctor came out and informed them that A Yong was in a coma due to alcohol poisoning. Chun Yu didn't believe it, while Zhang Tian Qiang firmly believed the doctor's words. Chun Yu felt that something was wrong with the doctor. If A Yong was in a coma due to poisoning, why did he end up in the haunted building? She asked about Hei Er's whereabouts going downstairs. Zhang Tian Qiang skeptically mentioned about A Yong being discharged from the hospital. Chun Yu remembered the broadcast from last night, saying that they had successfully cleared the level. It seemed that it was not just a dream.
Qing You became even more frightened and suggested calling the police, but Chun Yu said the police wouldn't believe their ghost stories, let alone the idea of shadow puppetry murder. Chun Yu received a call from her senior sister, informing them that they were going to be picked up and taken back to school. Zhang Tian Qiang reassured them to go and said that they would notify her as soon as A Yong woke up.
Before leaving, Chun Yu told him to continue searching for Hei Er, saying that he might know the answer. Gao Xuan had also mentioned the same thing to Zhang Tian Qiang. Nian Su Lan came to pick up Chun Yu and the others in her private car to return to school. Chun Yu recollected the events of the nightmare, and at that moment, Nian Su Lan received a call from Gao Xuan. He wanted to create a three-dimensional model but was lacking the blueprint for Building 19. He requested her to apply to the director for it.
Gao Xuan was now a graduate student and part-time substitute teacher at the school. Nian Su Lan proudly spoke about Gao Xuan and referred to him as her thesis advisor.
It seems that there is an organization researching brain-computer interfaces, and they took advantage of the accident to conduct brain-computer experiments on the people on the bus and the three individuals in the car. They connected the brain-computer interfaces to their brains, and Qing You's brain hemorrhage was a rejection reaction to the interface.
The higher-ups in the hospital or perhaps only that doctor are likely members of the organization. People who die on the nineteenth floor may undergo brain death and be replaced with vegetative states. Besides conducting experiments, the purpose of the brain-computer experiments may also involve selecting individuals.