Working as a dedicated detective lead Dahyun to a case of the death of a serial murderer, known to the public as 'Red Rose'. 2 years ago, he got away with the murder of 7 people, but was now found dead in his own apartment. One glance at the crime scene and anyone would conclude it to be plain suicide, but Dahyun thought otherwise. Join Detective Kim Dahyun as she unravels one of the most memorable murder cases she faced in her career.