The premise of this gag manga spinoff is about three high school students: a young male student, his girlfriend and a third wheel who is a One Piece fanatic. Their names are similar to the Straw Hat Pirates and the group form a fan club dedicated to One Piece.

After graduating from high school, Natsuko Hirose starts her career as an animator. Her talent quickly flourishes, and she makes her debut as a director in no time. Her first anime becomes a massive hit, sparking a social phenomenon and earning her recognition as an up-and-coming genius director. Her next project is set to be a romantic comedy movie themed around first love! However, having never been in love herself, Natsuko struggles to understand the concept of first love, and as a result, she's unable to create the storyboard, causing the movie production to come to a standstill. One day, she passes out while working on her storyboard and wakes up in the world of her favorite childhood anime movie "A Tale of Perishing."

There is only one person that high school student Saito Houjou truly cannot stand—and that is his temperamental classmate, Akane Sakuramori. The two have always been on bad terms; their contrasting views and personalities only lead to endless fighting. However, everything changes when Saito's grandfather and Akane's grandmother arrange a sudden meeting and insist that the two get married! Walking down the aisle is the last thing Saito and Akane want, but they are quickly coerced into accepting the ridiculous plan and soon move into a shared house as husband and wife. Although Saito and Akane despise each other, navigating life together under the same roof may just turn their bitter hatred into everlasting love.

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.