As a romantic comedy enthusiast, Yonosuke Eiyuu Sakai enjoys the stories about childhood friends the most. But he solemnly believes that the flawless, loving childhood friends from his stories exist only in fiction. Though he has two childhood friends of his own—Shio Minamo and Akari Hiodoshi—Eiyuu has never seen either one of them as anything more. However, now that they are all in high school together, the beauty of the two girls begins to catch Eiyuu's eye. As his interest subtly grows, the girls start to make advances toward him regardless of time or place—but only time will tell if Eiyuu will ever overcome his denial and finally see the girls in another light.

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.

Once believed to be extinct, ninjas have reappeared in contemporary Japan following the Pacific War. With a headcount rumored to be two hundred thousand, these deadly assassins are now tasked with covert operations, infiltrating a significant portion of the nation's public and private institutions in the process. Among these ninjas is Kurou Kumogakure, who often spends his days in a run-down apartment with no motivation to do much of anything. Some might consider him a useless vagrant who does nothing but steal beer from his neighbor. Nevertheless, the 17-year-old loser might actually be more dangerous than his demeanor suggests. Kurou's hidden potential is put to the test when he is given a new mission to infiltrate a local high school, but there is more to this assignment than he could ever predict.

Fable, an assassin who works in organized crime, has been raised to the legendary status of a ruthless killer capable of murdering any man within six seconds. Six years after his debut, his boss fears that Fable has started to attract too much attention from the legal authorities, and he orders him to hide in Osaka for a year. Accompanied by his driver who assumes the identity of his sister, Fable is bound by a special condition: he must act as a civilian and not murder anyone lest he and his partner lose their lives. However, the seemingly well-deserved holiday soon takes a grim turn. Takeshi Ebihara, the second-in-command of the Osaka mafia that officially protects the assassin, sees Fable's presence as a threat and wants to remove him. Constantly monitored by the yakuza and regularly put in life-or-death situations, Fable has no other choice but to outwit Takeshi's schemes if he wants to stay alive.