Miyu Suzuki is a high school girl whose cheerful outlook on life is tempered by her need to fit in. Coincidentally, beside her in the classroom sits Yuusuke Tani, a boy unconcerned with others' expectations. Their exchanges rarely extend beyond brief discourse, yet the polarity of their demeanors unexpectedly draws them to one another. As their mutual interest grows, the newfound feelings are no longer easy to ignore. Eventually, Suzuki voices what is inside her heart, forcing both of them to confront the unspoken affection between them. With each passing moment, their relationship evolves, and they gradually come to better understand themselves and the person who is their polar opposite.

After Sentouin D successfully infiltrated the Ranger Force in the disguise of Hibiki Sakurama, he is closer than ever to defeating the heroic Dragon Keepers. While strategizing his ideal placement in the Force, he discovers that he is assigned to the Green Squadron, whose main duty is to search and eradicate long-lost boss monsters. Joined by another new member, Angel Usukubo; their senior, Kanon Hisui; and a mysterious informant, Chidori, Sentouin D is first tasked with identifying suspicious activity in an abandoned school frequented by delinquents. During their investigation, they fall into a trap, and the group soon realizes that a boss monster is behind it all. Sentouin D must now find a way to escape alongside the others if he wants to continue pursuing his ultimate goal—achieving his ideal world free from boss monsters and the Dragon Keepers.

As a child living in the town of Lawless, Angelo Lagusa has witnessed a tragedy: his parents and younger brother have been mercilessly slaughtered by the Vanetti mafia family. Losing everything he holds dear, he leaves both his name and hometown behind, adopting the new identity of Avilio Bruno. Seven years later, Avilio finally has his chance for revenge when he receives a mysterious letter prompting him to return to Lawless. Obliging, he soon encounters the Vanetti don's son, Nero, and seeks to befriend him using the skills he has quietly honed for years. Set during the Prohibition era, 91 Days tells the story of Avilio's dark, bloodstained path to vengeance, as he slowly ends each of the men involved in the killing of his family.