Suletta Mercury leaves her planet and enters the Asticassia School of Technology at the behest of her mother. There, right and wrong are determined through duels between students, and the top-ranking duelist will receive Miorine Rembran as their fiancée—this prize being decided by Miorine's father. When Guel Jeturk, the best pilot in school and Miorine's current fiancé, demands that his betrothed move in with him, Suletta disapproves, so Guel challenges her. Although she emerges as champion, Suletta is subsequently detained on suspicion of piloting a forbidden type of mobile suit—a GUND-ARM, or "Gundam"—which results in her victory being voided. Miorine refuses to accept any more injustices and proposes another duel with even higher stakes. Now, Suletta must triumph a second time, otherwise she will be expelled and the Gundam Aerial that means so much to her will be destroyed.

In a Tokyo where gravity has broken, a boy and a girl are drawn to each other... The story is set in Tokyo, after bubbles that broke the laws of gravity rained down upon the world. Cut off from the outside world, Tokyo has become a playground for a group of young people who have lost their families, acting as a battlefield for parkour team battles as they leap from building to building. Hibiki, a young ace known for his dangerous play style, makes a reckless move one day and plummets into the gravity-bending sea. His life is saved by Uta, a girl with mysterious powers. The pair then hear a unique sound audible only to them. Why did Uta appear before Hibiki? Their encounter leads to a revelation that will change the world.

Akane Nishimura's quiet nature makes her classmates perceive her as a gloomy and unlikeable person. Combined with her intimidating gaze, it earns Akane the ominous nickname "Grim Reaper," condemning her to endless bullying for her supposed cursed powers that bring misfortune to everyone around her. However, none of these rumors deter transfer student Taiyou Takada from trying to befriend Akane. As someone who finds the supernatural fascinating, Taiyou approaches the Grim Reaper without hesitation, blissfully unaware of the complicated situation within the class. His bright personality and optimistic worldview may just bring about the change that Akane desperately needs.

It has been 800 years since the battle gods "Idaten", who boast overwhelming speed and strength, contained the "demons" who led the world to ruin after a fierce battle. "That battle" is now just an old tale in a distant myth. While the "peaceful generation of the gods," who have never fought since they were born, are out of peace, someone has revived the demons from a long sleep! Bring armed forces, wisdom, politics, conspiracy, whatever you can use! No-rule & no-limit three-way battle royale is about to begin!!! (Source: MAL News)