When Seiya Takano shows up at the detective agency “Holmes Agency,” he is accompanied by a large amount of freshly steamed Chinese manju. The staff members Ryosuke Noda and Kyoko Idemizu, who had been informed by the owner that the new leader was coming, were puzzled by the arrival of the gluttonous and greedy Seiya, who even carries his own “chopsticks”. Soon after, Seiya and the others head to the scene of a case that a well-known detective, Shuji Igarashi, is in charge of, since he happened to help catch a man who eats and drinks without paying. The case is a murder in Yokohama City. A man named Shoji Yamashita, who ran a real estate business, was strangled to death in his home. Seiya and the others watch over the investigation led by Momo Ogata, a female detective who seems to be a career detective. Shoji appears to have been killed by someone while eating sushi delivered from a restaurant.