Lee Hae Seong is a surgeon who is transferred, from one of the best hospitals in Seoul to a rundown hospital with no ER, after disobeying his previous hospital director, Park Geon. He then meets Jung Ddol Mi, an orthopedic resident from Busan, who came to Seoul to transfer a patient. Ddol Mi tries to meet professor Han Woo Jin, a cold robotic surgeon who works in Hae Seong's old hospital, before read moregoing back to Busan. However, she is stuck in Seoul after trying to save a patient. Meanwhile, a sinkhole appears in Seoul followed by a big earthquake that blocks all access to the city, causing phones, electricity, and water to not function. Hae Seong teams up with Ddol Mi to treat people, but soon medicine starts to runs out.