A murder occurs of a promising high school baseball player. His younger brother Shinya becomes the prime suspect. Private detective Koichiro is hired by their father, Saburo Moroka. To prove Shinya's innocence, Saburo, Koichiro, and Koichiro's pet dog Masa work to uncover the real killer's identity. At the same time, there is a case at a giant drug company named Mitsutomo Pharmaceuticals. Yuki bears a grudge against the company for prior inspection methods used over newly developed drugs. Yukie then threatens the company. Company president Kouta orders Kihara to resolve the problem discreetly. The more Kihara learns of the situation, the more hesitant he becomes about how to handle the situation. Finally, these two seemingly disparate cases cross paths, and a shocking truth emerges...
