Kang Dongjoo is one of the interns who have joined Geodae Hospital recently. He is notorious among his seniors for disobeying and playing smart. Yoon Seojeong gives advice to him that as an intern, he should follow whatever he's told without thinking. She further explains that the intern should put an elephant into a fridge even if it seems impossible.

Seojeong suddenly disappears one day after the car accident. Meanwhile, Dr. Do asks Dongjoo to operate a VIP patient and tells him to take it as an opportunity. Dongjoo accepts it but fails. Later on, Dongjoo receives a personnel order and heads to Doldam Hospital in Jeongseon, and meets someone there.

Master Kim and Dongjoo operates on Seojeong’s wrist as she cuts herself. During the operation, Dongjoo gets shocked with Master Kim’s speed and tries to follow his speed. Meanwhile, Master Kim kicks out Seojeong since he thinks of her as a mentally disturbed patient.

Seojeong gets caught while treating a patient even though she was kicked out by Master Kim. Master Kim gets furious about it and Seojeong goes to beg for his mercy. Dongjoo gets angry after finding it out and goes to face Master Kim. Meanwhile, Chairman Shin Myeongho visits Doldam Hospital to meet Master Kim.

Dongjoo comes to know that Master Kim is Dr. Boo Yongjoo and tries to stay back at Doldam Hospital to learn things from him. Finally, he gets a chance to perform a combine operation with Master Kim. Meanwhile, President Do Yoonwan asks Dr. Song Hyeoncheol to check on Master Kim by using Dongjoo. Therefore, he heads to Doldam Hospital with Do Inbeom.

Dongjoo goes to have lunch with Geodae Hospital staffs and hears something bad about Master Kim. Meanwhile, an emergency patient arrives at Doldam Hospital and Seojeong decides to operate on him with Inbeom as there is no one who can take care of it.

Dr. Song passes a letter of appointment to Mr. Jang Gitae and tells him that he is now Manager Jang. By passing the letter, Dr. Song asks Manager Jang to reveal every secret of Doldam Hospital. Meanwhile, Dongjoo and Inbeom get into a fight and Inbeom punches Dongjoo.

An armed man holds Seojeong as a hostage and barges into the operating room. He yells at Master Kim to stop the surgery, but Master Kim continues the surgery until the end. Meanwhile, Ms. Ji from Geodae Hospital comes to know about Seojeong’s PTSD history.

President Do comes to Doldam Hospital in order to explain himself to Chairman Shin. Seojeong ends up running away after writing a letter of resignation, but Dongjoo eventually finds her. Seojeong also gets a diagnosis that she does not suffer from PTSD, so she can happily return. Meanwhile, Ms. Woo Yeonhwa seems to have a secret.

Doldam Hospital faces extreme times when a rear-end collision involving six vehicles occur. As the traffic accident patients flood in, Mr. Choi from Internal Affairs’ daughter is also involved in the accident. Mr. Choi tries to stop Master Kim from performing any medical practices despite his daughter’s life is on the line.

President Do suggests an incredible offer to Dongjoo, so that he can bring Dongjoo over to his side. Master Kim comes to know about it but tells Dongjoo to decide his future on his own. Meanwhile, Seojeong comes to know about Master Kim’s pupil, Jang Hyeonjoo, through Jeong Insoo.

Parents of deserter find Dongjoo and ask him about the cause of their son’s death. However, Dongjoo hesitates to answer their question at first place. Meanwhile, the daughter of the sepsis patient who passed away due to Dongjoo’s operation on a VIP visits Doldam Hospital and holds a demonstration against Dongjoo.

Seojeong tries her best to be the first assistant of Chairman Shin’s operation and with her ceaseless efforts, Master Kim appoints her as the first assistant. Meanwhile, three suspected patients of MERS visit emergency room of Doldam Hospital, and Dongjoo decides to shut down the emergency room.

Seojeong decides to treat the patients in the emergency room after Dongjoo faints. At the same time, Master Kim receives the results of MERS test. Meanwhile, Dongjoo gets well and decides to get a Christmas present for Seojeong.

Uhm Hyeonjeong visits Doldam Hospital to stop Chairman Shin’s heart operation, but she gets shocked after hearing Chairman Shin’s test results. Master Kim asks Chairman Shin to cancel the operation as he has terminal lung cancer. Meanwhile, Dongjoo and Seojeong act like an enemy as they don’t want other staffs to know about their relationship.

Master Kim decides to do Chairman Shin’s operation. Master Kim tries his best to reduce the surgical time and Dongjoo helps him a lot by asking Inbeom to join them. Meanwhile, President Do plans to visit Doldam Hospital and suggests two options to Master Kim as he couldn’t stop Master Kim from the operation.

People start to gossip about Chairman Shin’s brain-dead condition on social network and President Do decides to take it as a great chance to shut Doldam Hospital down. Meanwhile, Reporter Oh calls Master Kim and asks him to reveal the truth about everything.

President Do publishes an article about Chairman Shin’s surgery without Master Kim’s name on it and invites the medical staff who participated in the operation. Meanwhile, Reporter Oh visits former nurse, Ms. No’s restaurant to find out about the truth.

President Do throws a punch at Master Kim as he was humiliated in front of people. President Do and Master Kim’s fight turns into a body battle and a giant ice sculpture falls on Master Kim’s body. Meanwhile, President Do visits Chairman Shin and beg for his help.