When Nam-Ra was requested by Bare-Su to allow Nam-Ra to bite Bare-Su at any body part (construction break-time), Cheong-San and the others were startled and discontented to see the lover eater Nam-Ra just make Bare-Su half-infected. After the bombing, Cheong-San faced important struggles with other friends on how to adapt sustainable better life at the quarantine base. He symphonizes gloomy On-Jo to rest assured about the process of the grievance on the losses from her father and the entire school.