Following the line of the precedent OVAs (of the same name) This anime goes around the normal lives of some elementary school (5th grade, 2nd class room) kids and their adventures, while turning to teens. Their games, stupid jokes, and the misunderstandings around their premature attraction to the opposite sex. Ryota Satou is the main character here, but his friends are almost as important as him since the school wouldn't be the same without them, especially the girls who the majority of time appear to be mature by their ages but in the ends they are as childish and even more "dangerous" than the boys. (Source: ANN, edited)

Eba Yuzuki has mysteriously decided to go to high school in the countryside. But despite Kirishima Haruto's objections, she is living in his home. Now he has to put up with a freeloading city girl and even worse, make sure Kanzaki Nanami, the girl he likes, doesn't get the wrong idea!

DVD/BD Extras.

Nen: the hidden source of energy and potential that runs through everyone, and gives those that master it a source of great power. Inside Nen is the potential for limitless light and limitless darkness. The Hunter Association has arisen to control access to it. Hunters come in many shapes and forms, and with many different appetites - but all of them have learned to master Nen, and use it to chase wealth, power, and their dreams. The greatest and most powerful Hunter is Isaac Netero, chairman of the Hunter Association. Decades ago he sealed away Jed, a Hunter who had mastered the use of On, the dark "shadow" of Nen. Now On users have reappeared at the Heaven's Arena "Battle Olympia" tournament. For Netero, this is the last mission: to protect the Association and the world from a threat driven by hatred and the thirst for revenge. And he's going to need all the help he can get in order to succeed.