After surviving a vampire attack, Koyomi Araragi notices that his friend and savior, Tsubasa Hanekawa, has been acting strange. When he happens to cross paths with her on his way to a bookstore and sees she has a bandage on her face, he knows something must definitely be wrong. Araragi wants to help her, but Hanekawa assures him that her wound is just something she received at home and that he should not concern himself with it. But when a white cat with no tail is hit and killed by a car, the pair bury the creature and the real trouble begins. When Araragi later pays a visit to his friend Meme Oshino and recounts the day's events, he is informed what they have buried is actually an apparition, one perfect for Hanekawa in her current state. Tasked with finding his friend to confirm her safety, he discovers that she has attacked her parents, possessed by the Sawari Neko. Now, it is up to Araragi to help Hanekawa as she once helped him.

When Keyaru acquired his powers as a Hero who specialized in healing all injuries regardless of severity, it seemed that he would walk the path to a great future. But what awaited him instead was great agony; he was subjected to years of seemingly endless hellish torture and abuse. Keyaru's healing skills allowed him to secretly collect the memories and abilities of those he treated, gradually making him stronger than anyone else. But by the time he reached his full potential, it was far too late—he had already lost everything. Determined to put his life back on track, Keyaru decided to unleash a powerful healing spell that rewound the entire world back to the time before he began to suffer his horrible fate. Equipped with the anguish of his past, he vows to redo everything in order to fulfill a new purpose—to exact revenge upon those who have wronged him.

Twenty-two-year-old college dropout Tatsuhiro Satou has been a hikikomori for almost four years now. In his isolation, he has come to believe in many obscure conspiracy theories, but there is one in particular which he holds unshakable faith in: the theory that the evil conspirator behind his shut-in NEET (Not in Employment, Education or Training) status is the Nihon Hikikomori Kyokai (NHK)—an evil and secret organization dedicated to fostering the spread of hikikomori culture. NHK ni Youkoso! is a psychological dramedy that follows Tatsuhiro as he strives to escape from the NHK's wicked machinations and the disease of self-wrought isolation, while struggling to even just leave his apartment and find a job. His unexpected encounter with the mysterious Misaki Nakahara might signal a reversal of fortune for Tatsuhiro, but with this meeting comes the inevitable cost of having to face his greatest fear—society.

After Keita Suminoe's mother passed away, his father promptly remarried, introducing two step-sisters into Keita's life: twins Ako and Riko. But since their fateful first encounter, a surge of incestuous love for their younger brother overcame the girls, beginning a lifelong feud for his heart. Now at the end of his middle school career, Keita studies fervently to be able to attend Ako and Riko's high school. While doing so however, he must resolve his conflicting feelings for his siblings and either reject or succumb to his sisters' intimate advances. Fortunately—or perhaps unfortunately for Keita—his sisters aren't the only women lusting after him, and there's no telling when the allure of temptation will get the better of the boy as well.