Imagine living life as the vice president of the student council, passing the days eating snacks, playing games, and bonding with a harem of beautiful girls. This is exactly the kind of life that high school student Ken Sugisaki leads, or so he thinks! Usually, the officers of Hekiyou Academy's student council are elected by popular vote, but an additional position is granted to the student who scores the highest on the exams. Ken, who historically has had below average grades, worked hard to improve them to be accepted into the student council, with the ultimate goal of surrounding himself with girls who fawn over him. Unfortunately for the vice president, things do not go quite as planned. Not only do the ladies of the council continually rebuff his advances, they also prefer to focus on more important and "boring" activities, such as organizing school events and managing the other clubs. But a few minor hurdles like these won't stop Ken from chasing after his dreams, even if they seem a bit ridiculous. [Written by MAL Rewrite]

The story begins with Hanabi, a sixth-grade girl who is neither an adult nor a child. She deals with issues such as accidentally witnessing her homeroom teacher kissing, and worrying about experiencing physiological changes before her friends. The series depicts a 12-year-old girl's innocent worries and first love. (Source: ANN)

Azmaria Hendrick gives some background information on characters and the setting, with flashback scenes from the Chrno Crusade series itself. Released with DVD volumes 2-12.

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]