Takanashi Yu, a former surgeon and internist, has been dispatched to the General Diagnostics Department of Teniikai General Hospital. The head of the General Diagnostics Department where patients who are deemed "difficult to diagnose" by each department are gathered is Ameku Takao. She is the niece of the hospital's director, Ameku Owashi, and also the deputy director. Takao's unique personality means that no one can control her behavior except for her sister, the administrative director Ameku Mazuru. Even the intern, Konoike Mai, calls her "Ameku Takao Theater." Takanashi is stunned by Takao's innocent and careless attitude, but at the same time he is amazed by her diagnostic abilities. Soon, truck driver Kagawa Shohei is involved in a traffic accident and is rushed to the hospital. Kagawa's hands shook and he lost consciousness immediately after eating a donut. The donuts he ate were from a company that has recently been involved in a series of incidents involving pesticide contamination and mass vomiting among consumers. However, no matter how many tests they do, no abnormalities are found in his body, and no poison is detected in the donuts recovered from the wrecked car. Takao and Takanashi take on the challenge of discovering the cause of this insurmountable illness...
