In Shinjuku ward's east side lies Kabukichou, a vibrant city of chaos that glows brilliantly with neon lights but also hides unseen darkness. Employed at a university hospital on the west side, John H. Watson is looking for someone who can assist him with an odd case. His search leads him to the Pipe Cat, an underground bar that serves as a meetup venue and job board for some of the best detectives in Shinjuku, the most prominent among them being Sherlock Holmes. Upon finding the bar and meeting the peculiar investigators, John learns that they are pursuing a case involving Jack the Ripper, an infamous serial killer. Due to subsequent events, John ends up driving Sherlock to the crime scene of a murder supposedly carried out by Jack the Ripper. Even though John is only there to enlist Sherlock's help with his case, he witnesses Sherlock brilliantly uncover the truth behind the crime scene. However, he begins to realize that Sherlock is not only a genius detective but also an eccentric character. As John continues to request Sherlock to assist him with his case, he finds himself spiraling into the detective lifestyle of solving cases beyond the minds of ordinary civilians. Through this work, John begins to see the true colors of the chaotic city that is Kabukichou and starts to unravel the unsettling mystery behind his own case.

At the renowned Shuchiin Academy, Miyuki Shirogane and Kaguya Shinomiya are the student body's top representatives. Ranked the top student in the nation and respected by peers and mentors alike, Miyuki serves as the student council president. Alongside him, the vice president Kaguya—eldest daughter of the wealthy Shinomiya family—excels in every field imaginable. They are the envy of the entire student body, regarded as the perfect couple. However, despite both having already developed feelings for the other, neither are willing to admit them. The first to confess loses, will be looked down upon, and will be considered the lesser. With their honor and pride at stake, Miyuki and Kaguya are both equally determined to be the one to emerge victorious on the battlefield of love!

Ruka Azumi's ordinary summer vacation revolves around spending all her time on the handball court to avoid her only housemate, her alcoholic mother. When an incident at practice leads to Ruka's exclusion from the handball team, she is forced to find other outlets to enjoy herself, eventually winding up at the aquarium where her father works. There, she meets Umi, a mysterious boy raised by dugongs who is being kept at the aquarium in order to research his strange water-dependent body. Ruka and Umi become fast friends, and the pair is soon joined by Sora, Umi's brother who also has an unusual relationship with the ocean. Together, the trio explore a dazzling undersea world while learning about a peculiar festival that all sea creatures around the world are preparing for.

As Yumeko Jabami's fame grows and the reputation of the student council dwindles, Kirari Momobami decides to revolutionize the group. To this end, she announces an election for its next president. The rules are simple: each student in the school receives one chip. Whoever has the most chips by the end of thirty days becomes both the new president and the head of the Momobami clan. Upon receiving news of this development, the Momobami branch families spring into action. Eleven transfer students arrive at Hyakkao Private Academy, each aiming to lead both the school and the Momobami clan. Equipped with unique talents, they will compete to get as many chips as possible—but their chips are not the only things on the line.