The fourth season of the popular medical drama starring Sakaguchi Kenji that portrays cutting-edge medical treatments in a thrilling overall package. Three years after the previous season, brilliant surgeon Asada Ryutaro (Sakaguchi) and his "Team Dragon" are back to achieve their goal of creating the perfect hospital where patients are the priority again. Two new exciting additions to the characters include Asada's former teacher (Hira Mikijiro) and a competent management consultant of the government (Takahashi Katsunori). The story in this season focuses on globalization.

Two best friends fall in love with an ordinary yet kind-hearted girl.

After Ke-luo's recognition party, Qi-xiang and Ke-luo finish cleaning up the studio. As they are rather tired, they start messing around and knock down a vase, which starts a fire. At the same time, Duo-li who just finished working overtime looked outside the window and saw smoke in the building across from hers. She hurriedly rushed out to check. Meanwhile, Qi-xiang and Ke-luo had quickly put out the fire and in the process, hurt Ke-luo's foot. Finding that the power got cut and the doors got locked, they decide to settle down and wait for help. Duo-li hurries and finds that there are people inside and help them call the police to open the doors for them. She waits outside with them until the cops arrive, then leaves, leaving Qi-xiang and Ke-luo mystified. Ke-luo feels a connection with Duo-li and asks Qi-xiang to find her for him. How will this end?

Waen is a single "dreamer" girl who wants to be a love novelist, but she never experienced love. One day, she finds a lost cat who ends up leading the way for her to meet Mai, but they don't get along and are always fighting. How will their relationship turn into love?

Amamiya Kuniyuki is the unemployed son of a tonkatsu restaurant owner. He finds a job that requires a married person, so he lies by saying that he has plans to marry, and he is forced to keep up the charade using Hida Haruno, a part-time worker from the restaurant. The relationship between the two is the key of this romantic comedy, though the series also focuses on family and friendship through Nakai's interactions with the other characters.

A story of young boys and girls who are in between jobs begins with a misunderstanding on them as an idol in the countryside. They are actually preparing together for job interviews in resort pension but start performing for African guests due to ruralists’ misunderstanding.

In Iryu 2, Asada Ryutaro wages a new battle against the realities of Japan's medical care system. The government has drafted legislation to tackle the recent inflation of medical fees; hospitals have entered an era in which they will go bankrupt if they aren't independently run. At the same time, hospital mergers and takeovers are also taking place. Additionally, the obstetrics and pediatrics departments are being closed in succession, and there are inadequate doctors in the region - issues that are closely related to these hospital management problems. Now, hospitals, like the average corporation, face collapse if they are not profitable.

Setoka Tachibana (Tao Tsuchiya) is a female high school student. She has confessed her feelings to other boys 12 times, but has been rebuffed each time. Her older brother Haruka Tachibana (Ryota Katayose) cares for his younger sister deeply, but he holds a secret from Setoka. The secret is that they are not blood related. One day, Setoka's first love Takane Serikawa (Yudai Chiba) appears after many years and approaches her.