As she arrives in Japan with her husband, Sunja must depend on the help of others. Solomon copes with the aftermath of his deal.

Sunja goes into premature labor while Baek Isak grapples with a political awakening. Solomon finds Hana, his long-lost love.

To make it out of the music room and onto the roof, the students put into action their most perilous plan yet. Elsewhere, Jae-ik comes across a setback.

Inside Lee Byeong-chan’s science lab, a student incurs a seemingly harmless bite. Shortly after, a fast-spreading outbreak soaks the school in blood.

The infected multiply in droves. Scrambling for their lives, Nam On-jo and Lee Cheong-san find safety with others inside a classroom — but not for long.

In need of a cellphone, two students take a risky journey to the teachers’ office. Byeong-chan passes on critical information to Detective Song Jae-ik.

To make it out of the music room and onto the roof, the students put into action their most perilous plan yet. Elsewhere, Jae-ik comes across a setback.

The infected multiply in droves. Scrambling for their lives, Nam On-jo and Lee Cheong-san find safety with others inside a classroom — but not for long.

In need of a cellphone, two students take a risky journey to the teachers’ office. Byeong-chan passes on critical information to Detective Song Jae-ik.

Inside Lee Byeong-chan’s science lab, a student incurs a seemingly harmless bite. Shortly after, a fast-spreading outbreak soaks the school in blood.

Intent on changing Ji-woo’s mind about carrying out her vengeance, Pil-do handcuffs himself to her. Mu-jin reacts to another act of betrayal.

On her birthday, Yoon Ji-woo witnesses the horrific death of her father. Hell-bent on taking revenge at any cost, she sets out to find his killer.

A photo in the mail revealing obscured truths casts everything Ji-woo thought she believed into doubt. Mu-jin moves to protect his interests.