The protagonist of the story, Konoha Inoue, is a seemingly normal senior high 2nd year student. His high school life, other than a hinted incident 2 years ago, can be summed up as normal- if one can dismiss the secret fact that he used to be a female bestselling romance author. Due to that incident, however, he has now vowed never to write again. This continued on until he was forced to join the literary club by the literary club president, the 3rd year female student Amano Tooko, a beautiful girl who has a taste for eating literary works. Now he has been tasked with writing her snack every day after school.

Episodes 1-3 focus on Dera welcoming ladies to his bar. Episodes 4-6 focus on Choi-chan.

After the final downfall of the rogue Bakugan Naga, peace was brought back to Vestroia. With the help of Danma Kuusou, his companion Pyrus Dragonoid, and other Battle Brawlers, the Infinity and Silent Cores were combined and the realm was recreated. However, New Vestroia will not be given any respite as humanoid alien invaders, the Vestals, arrive and conquer the Bakugan world in one fell swoop. Armed with a fearsome machine capable of restricting Bakugan into their ball forms, they aim to enslave the race as a form of entertainment. Now, the only force standing in their way is the Bakugan Battle Brawlers Resistance—a group of humans, Bakugan, and Vestals who oppose the idea of annihilating a sentient race. Led by Danma, they must venture into enemy-occupied New Vestroia and repel the invaders, to assure the survival of the entire world. [Written by MAL Rewrite]

Reaching a period of life where they are neither a child nor an adult, 12-year-old Hanabi Ayase and Aoi Yui meet with life-changing events. Due to the mischievous demeanor of her male classmates, Ayase does not think highly of the opposite sex. However, her perspective begins to change after she is paired with the kind-hearted Takao Yuuto for a class assignment and unexpectedly shared their first kisses with each other on the school rooftop. With her best friend discovering love, Aoi yearns to seek her own. She finds herself falling in love with the rash Kazuma Hiyama after protecting her from a rejected suitor who had talked behind her back. 12-sai.: Chicchana Mune no Tokimeki follows the four in this phase of adolescence. As they grow up alongside each other, this sweet romance depicts the innocence and excitement of first love. [Written by MAL Rewrite]