The distant future. After reaching its peak, Earth's population fell into decline. AI was developed to help preserve the species and manage the ecosystem; a grand experiment in human diversity. Through genetic engineering, a diverse array of peoples, including beastfolk, magical beings, and more, was created to live in a diverse city separated into walled "clusters". Each cluster developed a unique culture, befitting of the people that lived there. Their lives, and the system, is continually maintained by the AI to ensure survival.

After inheriting the company from their parents, siblings Yuuhi and Yuamu Oudou have started to work at Ultraterrestrial Trouble Solutions, an organization that hunts aliens. Although they have never encountered aliens before, Yuuhi is desperate to meet one as he believes that an alien has stolen his important item called the "Earthdamar." One day, while searching for extraterrestrial creatures, Yuuhi and Yuamu find a strange spot in the forest where many trees have fallen, forming a scenery similar to a crop circle. As they venture further, they discover a mysterious spaceship and enter it out of curiosity. To their surprise, they come across Yudias Velgear, an alien from the Velgear Star Cluster. As it turns out, Yudias is seeking to learn about Rush Duel—a card game popular among elementary school students—as he believes that it will save his home from a long war. With the siblings agreeing to teach Yudias about Rush Duel, they eventually realize that their first contact with an alien may not be a random coincidence.

General of the Three Kingdoms, Kongming had struggled his whole life, facing countless battles that made him into the accomplished strategist he was. So on his deathbed, he wished only to be reborn into a peaceful world... and was sent straight to modern-day party-central, Tokyo! Can even a brilliant strategist like Kongming adapt to the wild beats and even wilder party people?!