A sudden explosion creates numerous casualties; Hae-seong, Ttol-mi, and Ji-na are all on the scene.

A 6.5 earthquake hits the city of Seoul; Hae-seong and Ttol-mi attempt to treat the injured.

There are people who are still alive under a pile of concrete; Hae-seong makes a difficult decision.

Doctors perform triage on the victims, but Director Park and Han U-jin have a different plan.

Mirae Hospital is running out of electricity, and Director Park prepares for a complete shutdown.

After going to search for a blood bank, Hae-seong returns to Mirae Hospital injured and unconscious.

The hospital depletes its resources, yet rescues continue and victims pour in.

U-jin complains of dizziness; a crisis strikes the ER as multiple patients go into cardiac arrest.

Director Park and Kang Ju-ran, head of ER, argue over whether to close the hospital.

While treating an elderly man and a young boy, Hae-seong experiences severe anxiety symptoms.

Hae-seong locks himself up in his room; Director Park vows to make him pay for his misjudgment.

Hae-seong studies to tackle a complicated surgery that no other doctor is willing to perform.

Director Park is asked to perform neurosurgery on a VIP patient who is in critical condition.

Director Park calls for an executive meeting to discuss Hae-seong's qualifications.

Director Park's struggle for power turns into a battle of pride between himself and Hae-seong.

Congressman Gu Ja-hyeok gets into a confrontation with the head of the fire crew.

Not able to trust another doctor with her father, Ttol-mi pleads for Hae-seong's help.

Mirae Hospital's doctors return to work; Director Park plans his revenge against Hae-seong.

Hae-seong faces the hardest decision he's had to make since he became a doctor.