Shiroki Tsubasa and Amami Nanato were your run-off-the-mill pair of childhood friends. But after their parents decided to declare them fiancées, they both grew more conscious of the other, and right as a sweet and heartwarming romcom would have awaited them—Nanato was forced to move away with his mother! Five years later, however, the two of them are reunited during their first year of high school. Tsubasa aims to tell Nanato of the feelings she had kept all these years, but Nanato’s new gal friend and rival Chiba Reina won’t let her! Once the both of them realize they each hold feelings for Nanato, they decide on a bet: The one who makes Nanato confess to them wins! But what happens when both girls have practically zero experience to show and fail at every attempt of seducing Nanato?! And will the old-fashioned promise of being fiancées triumph over everything after all?!