Mari Tamaki is in her second year of high school and wants to start something. It's then that she meets Shirase, a girl with few friends who's considered weirdo by the rest of the class and nicknamed...

The Abyss—a gaping chasm stretching down into the depths of the earth, filled with mysterious creatures and relics from a time long past. How did it come to be? What lies at the bottom? Countless brav...