Five distinct worlds—Black, White, Green, Red, and Blue—are connected by the "Halo" and maintain a harmonious balance. However, the Halo suddenly opens during an event called the World Connect, putting the universe at risk of destruction. Under attack by Ouroboros, an alien race seeking to hasten the end of the universe, the five worlds recruit girls possessing special abilities known as Exceed to defend against them. Saya Sougetsu, a young girl from the Blue World of Earth, is one such individual capable of wielding Exceed power. Seeing this as her opportunity to make a difference, Saya eagerly joins the defense force. There, she encounters Amane Ayashiro, another girl from Earth, along with a group of fighters from the other worlds. Confronted with a powerful enemy, the girls must demonstrate that their new bonds are strong enough to secure the future.