Kio is just another boring, nice guy with a boring, nice life until he meets a beautiful, curvaceous cat-girl while attending a memorial service for one of his ancestors. Next thing he knows, he's lying in bed with this half-naked beauty next to him! Her name is Eris, and she has come to Earth to learn more about its inhabitants as a representative of the planet Catian. And she's decided to set up shop at Kio's home for her stay on Earth! Unbeknownst to Kio, there are quite a few organizations who will attempt to capture Eris, looking to keep her existence a secret by any means necessary. What's worse is when people around Kio turn out to secretly be a part of those organizations! Kio will have to work hard to keep Eris safe from these shady groups. Things are about to get mysterious, exciting, and most importantly sexy in Asobi ni Iku yo!

Long ago, a goddess descended from Heaven and blessed the desolate land of Gatepia. As a result, gigantic gates appeared, leading to dungeons abundant in "kirakuri," crystals containing the energy needed for the foundation of the world. This led to the formation of various companies of adventurers who would harvest kirakuri from the dungeons. Following his father's disappearance inside one of the biggest gates in Gatepia, Minato is urged by his childhood friend Yutoria to become the president of his father's treasure-hunting company—the Kibou Company. He reluctantly agrees and meets with the other employees: the priest Makoto, the soldier Akari, and the accountant Guide. Thus, Makoto begins his tenure as president. As he and his comrades strive to fulfill various missions and other assorted tasks in order to keep their small company alive, they will uncover the mystery behind their former leader's sudden departure.

After fending off the threat of a Neuroi invasion of Romagna and destroying the enemy's nest over Venezia, Yoshika Miyafuji goes back to her home town in the Empire of Fusou. Despite the loss of her magical and healing abilities, the former officer of the 501st Joint Fighter Wing wants to continue studying medicine. This is in order to help those in need, both civilians and those on the front lines alike. She receives an invitation from a prestigious school in Europe and decides to accept the offer, embarking on a journey back to the war-torn continent. However, a new danger arises, as more and more Neuroi manage to break through human defense lines, appearing unnoticed in supposedly safe areas and disturbing the balance of power in Europe. Yoshiki's sense of duty collides with her inability to pilot a Striker Unit, but with her friends in peril, it seems that there is only one thing she can do.

Chibi-style special episodes of .