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.