Coo no Sekai

Seventh grader Hayashi Renei is haunted by a recurring dream that blurs the line between memory and nightmare. Each night, she finds herself visiting her older brother, who was tragically killed in a car accident. However, he does not appear as she remembers him; instead, he has been reborn within this dreamscape as a being known as Coo. What begins as a single strange vision soon becomes an inescapable nightly occurrence, pulling Renei deeper into a surreal realm with every passing sleep. This alternate dimension, referred to as Coo's world, proves to be far more merciless than reality. It is a landscape defined by profound pain, suffering, and sorrow, surpassing even the grief Renei endures in her waking life. Trapped within this harsh environment, she must navigate its dangers alongside her transformed brother and the various individuals she encounters along the way. Her ultimate goal is to locate her house within this distorted realm—the key to breaking free from the dream. Only by finding it can Renei escape Coo's cruel world and return safely to reality and the land of the living.