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.

In a Kaiju-filled Japan, Kafka Hibino works in monster disposal. After reuniting with his childhood friend Mina Ashiro, a rising star in the anti-Kaiju Defense Force, he decides to pursue his abandoned dream of joining the Force... when he suddenly transforms into the powerful "Kaiju No. 8." With help from his junior colleague Reno Ichikawa, Kafka hides his identity while striving towards his life-long dream of passing the Defense Force exam and standing at Mina's side. But when mysterious intelligent Kaiju attack a Defense Force base, Kafka faces a crucial decision in a desperate situation...

With its flickering streetlights, moldy back alleys, and noisy populace, the Second Kowloon Walled City, despite the squalor of its already-demolished predecessor, evokes a special kind of nostalgia that its residents find endearing. Amidst the walls of this fading yet beloved landscape lives Reiko Kujirai, a 32-year-old realtor deeply in love with her coworker, Hajime Kudou, who is two years her junior. Though they have their differences, the two get along well enough to experience the joys of the walled city together. However, everything starts to fall apart when Kudou, half-asleep, suddenly kisses Kujirai—seemingly reciprocating the feelings she has yet to confess. But when Kudou explains that he had mistaken her for someone else, Kujirai finds herself drawn into a series of events that lead her to a past she cannot remember.

"I can't do this anymore!" Yuke Feldio, a red mage, just left his adventurer A-Rank party. After being mistreated as a handyman and ridiculed for five years, he finally snapped! And so began his desolate, unemployed life... or so he thought! Through a stroke of luck, Yuke is welcomed into an all-female adventurer party comprised of his former students!! As they defeat dungeons one after another, Yuke's true strength is gradually revealed! As it turns out, this red mage wields extraordinary magic and skills?!