Drowning in a Dry Room [Part 1] Yu is to be reassigned to Junsei University Hospital's General Medicine department to replace a doctor who can no longer work. Takao discovers the doctor, Kuwata Seiji, is a murder suspect. Meeting with Seiji's father Ryuichiro they learn Seiji is suspected of murdering his brother Daiki, who drowned alone in a locked room despite there being no water. Ryuichiro admits he hadn't seen Daiki in years, having disinherited him. He also admits Seiji was the son of his mistress, and when Daiki's mother found out she became unstable and eventually killed herself. The day Daiki died he had crashed Ryuichiro's 70th birthday party and attacked Seiji. Hours later Daiki called Ryuichiro from Ryuichiro's office in the house begging for help. Ryuichiro, his brother Kojiro, and a hospital employee rushed to the office which was locked, requiring Ryuichiro to unlock the door, and they found Daiki with his lungs filled with water. Daiki later died in hospital. Fearing Seiji may be involved, Ryuichiro had Daiki's cause of death listed as an illness, then cremated him without an autopsy. As a result the police suspect Daiki was murdered by Seiji and Ryuichiro tried to cover it up. Takao examines the study and Ryuichiro explains the door is normally unlocked and the only keys belong to him and Seiji. Seiji also has no alibi since instead of going to hospital after being attacked he claims he sat in his car for two hours. Takao interviews Dr. Akira who examined Daiki while he was still alive and confirms Daiki had water in his lungs. Dr. Yuko also confirms she didn't treat Seiji's head injuries from Daiki until the day after Daiki died. Takao argues with Yu and reveals she only wants to solve Daiki's murder so Seiji can return to his job and Yu won't have to transfer.