Yani is a catgirl with a seriously bad smoking habit. She smokes so much that her apartment smells like ash and is littered with cigarette butts—and plenty of other trash! Every time she tries to quit, she becomes weak to the cravings and gives in almost instantly. Will she ever get her life together, or is she doomed to live as a chainsmoking slob forever? (Source: Seven Seas Entertainment)

Rentarou Aijou has it all: looks, intelligence, athletic skill, and popularity with peers and mentors alike. Unfortunately, none of these qualities help Rentarou with his love life. On the day of his middle school graduation, he is once again turned down by a girl he confesses to, earning his one-hundredth rejection in a row. Down on his luck, he goes to a matchmaking shrine and wishes to finally get a girlfriend in high school. When the god of the shrine suddenly appears before him, Rentarou is told he will meet an astronomical total of one hundred soulmates in high school. Though Rentarou initially does not take this foretelling seriously, his doubts disappear when, on the first day of school, he meets two of these soulmates—Hakari Hanazono and Karane Inda—who both confess to him. With fated encounters and love confessions galore, Rentarou's life is about to get a lot more exciting.

Ever since Rentarou Aijou found out that he would meet a total of one hundred soulmates in high school, his life has been anything but boring. Now with six girlfriends—each with their own unique quirks—Rentarou has never been happier. The group expands once again when Rentarou meets Kurumi Haraga, a girl with a never-ending appetite; and Mei Meido, the maid of the Hanazono family. As he encounters more of his soulmates, Rentarou has to juggle ways to date them all, since failure results in a grim fate. Fortunately, Rentarou has no shortage of love to give to each of his girlfriends!

Through their tutor Fuutarou Uesugi's diligent guidance, the Nakano quintuplets' academic performance shows signs of improvement, even if their path to graduation is still rocky. However, as they continue to cause various situations that delay any actual tutoring, Fuutarou becomes increasingly involved with their personal lives, further complicating their relationship with each other. On another note, Fuutarou slowly begins to realize the existence of a possible connection between him and the past he believes to have shared with one of the five girls. With everyone's feelings beginning to develop and overlap, will they be able to keep their bond strictly to that of a teacher and his students—or will it mature into something else entirely?