ER Doctor: My Sister's Best Friend Has Been Clinging to Me from the Start

Lu Zhou, an emergency room doctor, is publicly betrayed and dumped by his girlfriend of many years. Then, by chance, he sleeps with Su Muhan, a stunningly beautiful and aloof woman, and awakens the Divine Doctor Evolution System.

With a single glance, he can see through the source of an illness, and hands-on surgery raises his medical skill level.

His ex-girlfriend and coworkers make things difficult for him at every turn. Backed by the deputy director's influence, they sabotage him, spread rumors and slander, and try to drive him out of the hospital.

A chain-reaction car crash occurs. Lu Zhou rushes into action, accurately assessing the injuries of critically wounded patients with nothing but his eyes. He predicts a hidden intracranial hemorrhage, but his diagnosis is questioned.

In the end, the patient falls into a deep coma and suffers an acute cerebral hemorrhage. Just as everyone is ready to give up, Lu Zhou uses the System to pull the patient back from the brink of death, proving them all wrong and leaving them in awe.

The new director, Su Muhan, starts to fall for him, completely unaware that Lu Zhou is the man she spent a night with.

Repeated near misses and misunderstandings outside the hospital keep them from learning each other's identities.

Inside the hospital, they both wear masks, and a series of coincidences makes them miss each other again and again, never meeting face-to-face.

In these circumstances, Su Muhan is repeatedly impressed by Lu Zhou's abilities, and eventually develops feelings for him.

Then, by chance, they finally meet, and all the misunderstandings and coincidences are resolved once and for all that day...