Adult life has brought its share of disillusions to 28-year-old writer Sumireko Ogawa, who was once considered a child prodigy in literature. Facing hostility from editors, she struggles to publish her work and progress in writing her new novel. As Sumireko starts to resign herself to the uneventful life of a book clerk, she is brutally plunged into the realm of mysteries after she reads poetry from a strange book, as she unexpectedly becomes a child again.

Sumireko is thrilled to have regained her inspiration and youthful enthusiasm. However, her work colleague Ren Adashino, who happens to be an expert in the occult, warns her that this transformation will eventually kill her unless she reads other verses from the book. Reluctantly agreeing to regain her adult form, Sumireko decides to help Ren and his sister, Oto, in their paranormal investigations. Although Ren's goals are still unclear to Sumireko, the young woman is determined to turn her new exciting life experiences into a lasting literary success.

Kaii to Otome to Kamikakushi was released on Blu-ray and DVD in two volumes from July 24, 2024, to August 28, 2024.