As technology advanced, humanity gradually colonized the entire solar system, occupying planetary facilities from Mercury to Pluto. This results in a large-scale athletic tournament, the "Daiundoukai," where several aspiring female athletes from all around the solar system compete. The winner of the tournament is crowned the "Cosmo Beauty," obtaining a queenlike status. When outgoing potato farmer Kanata Akehoshi was a child, she witnessed a meteor-like object falling from the sky, crashing in a nearby forest. When she came to investigate the wreckage, she saw a damaged spaceship and a girl who seemed to have been in it weakened by the impact. The girl gave Kanata two wristbands, alongside a request that Kanata join the Daiundoukai and become the Cosmo Beauty. Kanata obliged, but before she could ask for the girl's name, she mysteriously disappeared—leaving nothing,not even the crater caused by the crash. Since then, Kanata has devoted herself to training, aiming to fulfill her promise. After winning the qualifying round to represent the planet Earth, Kanata goes to the University Satellite—an institution where she and other candidates study to prepare themselves for the upcoming competition. There, she meets and befriends her fellow competitors, helping them get along with each other to perform better in the games. As Kanata grows closer to the coveted title, so do her chances of meeting the girl who changed her fate—and she discovers an underlying mystery behind the Daiundoukai along the way.

The story follows Iruma Suzuki, a 14-year-old human boy, who is sold to a demon by his parents. The demon, known as Sullivan, takes Iruma to the Demon World and officially adopts him as his grandson. He enrolls Iruma in the Babyls School for Demons where he is the headmaster and where Iruma quickly befriends the demons Alice Asmodeus and Clara Valac. However, Sullivan tells Iruma to never reveal that he is human since he will be eaten if anyone finds out. Iruma then vows to blend in during his time in the demon world, although he only stands out because of all the situations and adventures that arise.

Shamisen is a traditional Japanese musical instrument that looks similar to a guitar. Teenager Sawamura Setsu's grandfather who raised him and his older brother Wakana, recently passed away. His grandfather was one of the greatest Shamisen players and the two siblings grew up listening to him play and learning to play the instrument. Since their grandfather's death, Setsu dropped out of high school, moved to Tokyo and has been drifting, not knowing what to do besides play his Shamisen. That's when his successful and rich mother, Umeko, storms into his life and tries to shape Setsu up. She enrolls him back into high school, but little does Setsu know that he is about to rediscover his passion for Shamisen. (Source: MU, edited)

The Republic of San Magnolia. For a long time, this country has been besieged by its neighbor, the Giadian Empire, which created a series of unmanned drones called the Legion. After years of painstaking research, the Republic finally developed autonomous drones of their own, turning the one-sided struggle into a war without casualties—or at least, that's what the government claims. In truth, there is no such thing as a bloodless war. Beyond the fortified walls protecting the eighty-five Republic territories lies the "nonexistent" Eighty-Sixth Sector. The young men and women of this forsaken land are branded the Eighty-Six and, stripped of their humanity, pilot the "unmanned" weapons into battle... Shinn directs the actions of a detachment of young Eighty-Sixers while on the battlefield. Lena is a "handler" who commands the detachment from the remote rear with the help of special communication. The farewell story of the severe and sad struggle of these two begins! (Source: MU, Yen Press; edited)