"Tul's" first field visit after just moving to work was not smooth. To make matters worse, he had to work with "Cherran", the forensic doctor in charge of the case. Both of them have very different personalities and attitudes, which made them not get along very well. Not to mention the social pressures they had to face when all the cases were in the public eye, which all affected the cases. However, when there were opportunities for them to work together more often, their relationship started to improve. However, the story was more complicated than expected when one day a murder occurred that was similar to the one that a serial killer had committed 18 years ago. Was this the work of the "Raindrop Killer" or was it a copycat of another killer?