Based on the autobiography of the singer Kawashima Ai. The name of the book is "Saigo no Kotoba" ("The Last Words") and it follows Kawashima Ai's life after her mother's death. The story chronicles her journey to make her dream come true to be a singer and, among other things, how she used to perform for free on Tokyo's streets.

The year is 2222. It has been years since Tears of the New Moon, a mysterious rain, poured and wiped out almost the entire human race. The poisonous rain gave birth to deformed creatures devouring humans, and humanity fled from the danger. As means for survival, the humans then build an underground haven; Amasia. In this newly built dystopian city, in a pursuit of maintaining their existence, they run into an Artificial Intelligence named Magus. Not knowing how things will work between them, the story of how Humans and AI coinciding and trying to find their truths begin.

Lina and Gourry travel to a seaside town named Acassi, where octopus tentacle is a delicacy. However, the octopus meat carries a curse that dooms the eater to only speak Takogo (octopus language). Amelia, Zelgadiss, and Xelloss all show up, and the main four characters (Lina, Gourry, Ameria, Zelgadiss) get cursed. The octopi enlist the power of a mazoku to get rid of the humans once and for all. The white sorceress Ruma must learn the cure to the curse from her long-lost master in order to save the town. 

After surviving the entrance exams, Sakuta Azusagawa has finally enrolled in the same university as his girlfriend, Mai Sakurajima. He is gradually getting used to the unfamiliar environment as he attends student gatherings and makes new acquaintances. Everything seems to be going smoothly until Sakuta's friend and Sweet Bullet idol group member Uzuki Hirokawa begins acting out. With fellow Sweet Bullet member Nodoka Toyohama pleading for his help, Sakuta realizes that he has stumbled upon another case of the inexplicable Puberty Syndrome—Uzuki is feeling pressured by the sudden surge of popularity and rumors of a potential solo career. While Sakuta searches for a solution, another occurrence of Puberty Syndrome gradually emerges from the shadows.