Brutal murders, petty thefts, and senseless violence pollute the human world. In contrast, the realm of death gods is a humdrum, unchanging gambling den. The ingenious 17-year-old Japanese student Light Yagami and sadistic god of death Ryuk share one belief: their worlds are rotten. For his own amusement, Ryuk drops his Death Note into the human world. Light stumbles upon it, deeming the first of its rules ridiculous: the human whose name is written in this note shall die. However, the temptation is too great, and Light experiments by writing a felon's name, which disturbingly enacts his first murder. Aware of the terrifying godlike power that has fallen into his hands, Light—under the alias Kira—follows his wicked sense of justice with the ultimate goal of cleansing the world of all evil-doers. The meticulous mastermind detective L is already on his trail, but as Light's brilliance rivals L's, the grand chase for Kira turns into an intense battle of wits that can only end when one of them is dead.

The rare and inexplicable Puberty Syndrome is thought of as a myth. It is a rare disease which only affects teenagers, and its symptoms are so supernatural that hardly anyone recognizes it as a legitimate occurrence. However, high school student Sakuta Azusagawa knows from personal experience that it is very much real, and happens to be quite prevalent in his school. Mai Sakurajima is a third-year high school student who gained fame in her youth as a child actress, but recently halted her promising career for reasons unknown to the public. With an air of unapproachability, she is well known throughout the school, but none dare interact with her—that is until Sakuta sees her wandering the library in a bunny girl costume. Despite the getup, no one seems to notice her, and after confronting her, he realizes that she is another victim of Puberty Syndrome. As Sakuta tries to help Mai through her predicament, his actions bring him into contact with more girls afflicted with the elusive disease.

Thirty-seven-year-old Satoru Mikami is a typical corporate worker, who is perfectly content with his monotonous lifestyle in Tokyo, other than failing to nail down a girlfriend even once throughout his life. In the midst of a casual encounter with his colleague, he falls victim to a random assailant on the streets and is stabbed. However, while succumbing to his injuries, a peculiar voice echoes in his mind, and recites a bunch of commands which the dying man cannot make sense of. When Satoru regains consciousness, he discovers that he has reincarnated as a goop of slime in an unfamiliar realm. In doing so, he acquires newfound skills—notably, the power to devour anything and mimic its appearance and abilities. He then stumbles upon the sealed Catastrophe-level monster Storm Dragon Veldora who had been sealed away for the past 300 years for devastating a town to ashes. Sympathetic to his predicament, Satoru befriends him, promising to assist in destroying the seal. In return, Veldora bestows upon him the name Rimuru Tempest to grant him divine protection. Now, liberated from the mundanities of his past life, Rimuru embarks on a fresh journey with a distinct goal in mind. As he grows accustomed to his new physique, his gooey antics ripple throughout the world, gradually altering his fate.

Fuutarou Uesugi is an ace high school student, but leads an otherwise tough life. His standoffish personality and reclusive nature have left him friendless, and his father is debt-ridden, forcing his family to scrape by. One day during his lunch break, Uesugi argues with a female transfer student who has claimed his seat, leading both of them to dislike each other. That same day, he is presented with a golden opportunity to clear his family's debt: a private tutoring gig for a wealthy family's daughter, with a wage of five times the market price. He accepts the proposal, but is horrified to discover that the client, Itsuki Nakano, is the girl he confronted earlier! After unsuccessfully trying to get back on Itsuki's good side, Uesugi finds out that his problems don't end there: Itsuki is actually a quintuplet, so in addition to her, he must also tutor her sisters—Miku, Yotsuba, Nino, and Ichika—who, despite the very real threat of flunking, want nothing to do with a tutor. However, his family's livelihood is on the line so Uesugi pushes on, adamant in his resolve to rid the sisters of their detest for studying and successfully lead them to graduation.