Sae Bom finally gets to be a homeowner. At the end of all her hard work, she thought happiness was just around the corner. However, she ends up learning she might have caught a new contagion, one that causes the infected to bite people after losing their minds. Even though Sae Bom and Seung Young are under an oath of secrecy, reporters approach them with a hefty sum of money. Meanwhile, Yi Hyun and Tae Seok from the Central Disaster Countermeasures Headquarters (CDCH) join forces to find out the true nature of the disease.