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.
A military leaflet promises a route to safety, but the group is reluctant to trust it. Hyun-su is exposed to a new perspective on his condition.
Hyun-su wakes up to find Sang-wook, who has a new goal for them. Lee Eun-yu and Ji-su escape a violent evacuation and commandeer their next destination.
Eun-yu finds a hint of Eun-hyeok’s fate at a stop in her journey. During an experiment, Hyun-su finds that he has a special effect on another monster.
On a mission to find her husband, Yi-kyung makes a shocking discovery. The battered Ji-su and Eun-yu arrive at a new shelter, but catastrophe awaits them.
The survivors take shelter underground, where supplies run low. In her continued search for Eun-hyeok, Eun-yu encounters a young girl.
Sergeant Kim and Master Sergeant Tak clash on how to protect their men. The mysterious girl approaches Eun-yu with an enticing offer.
Eun-yu chases Yi-kyung and the girl, with Park Chan-yeong right behind her. The death of survivors and a missing soldier throws the stadium into unrest.
Eun-yu shares a terse reunion with Hyun-su. While the platoon embarks on their search for a missing soldier, the stadium experiences a monster threat.
As Yi-kyung faces death, the young girl tries to save her. In the ruins of the lab, the soldiers discover other survivors who aren't what they seem.
Hyun-su gives it his all to bring Yi-kyung’s humanity back. Sergeant Kim faces countless monsters in an effort to make it out alive with his men.
Resolved to find the child, Sang-wook heads to the stadium. Despite Hyun-su's unpredictability, Eun-yu tries to wake him up during a sudden crisis.
Yi-kyung discovers Sang-wook's true motive for her daughter. Eun-yu accepts a challenge from Hyun-su's alter ego and heads to the stadium.
The girl contemplates her future with Yi-kyung — and a life away from Sang-wook. Sergeant Kim encounters Eun-hyeok, who reveals a new kind of being.
Eun-hyeok's reunion with Hyun-su and Eun-yu turns into chaos. Sang-wook prepares for his body transfer, while Sergeant Tak carries out his own plan.
In her trek to the stadium, Eun-yu begins to feel a personal worry. While Sang-wook searches for the girl, she plans a counterattack in the background.
Hyun-su and Eun-hyeok arrive at the stadium, splitting up to find Sang-wook. During the great escape, Sergeant Tak commits the ultimate sacrifice.
In the final battle, Hyun-su and Eun-hyeok confront the girl head-on — getting an assist from an old friend. Will they finally succeed?