Cha Hyun-su moves into the run-down Green Home by himself. Not long after, he witnesses a disturbing sight in his neighbor's apartment.

As a state of emergency is declared, the residents tie up Pyeon Sang-wook for being bitten. Hyun-su is unable to ignore a family in distress.

An unexpected savior protects the children from harm as Hyun-su, together with Yoon Ji-su and Jung Jae-heon, tries to bring them to safety.

Critical information about the monsters is made public. When residents are split on what to do with Hyun-su, Lee Eun-hyeok suggests they hold a vote.

Tasked to carry out dangerous missions, Hyun-su heads back to retrieve Han Du-sik. Sang-wook stops at nothing to finish what he started.

An Seon-yeong confronts the greatest monster in her life. Leaving the building, Seo Yi-kyung heads to her fiancé's office in search of answers.

Hyun-su saves the others from a deadly attack. Running out of necessities, Eun-hyeok announces a plan to venture outside for resources.

Having little options in her state of being, Ji-su agrees to take a big risk. Yi-kyung returns to Green Home just in time.

When a team of outlaws take over the building, the residents are shown how humans can be even more barbaric than the monsters.