Michi has been burdened her entire life by the ability to see ghosts, so she has developed a strict policy of pretending she cannot see them in order to avoid any involvement. That policy is put to the test when she encounters a ghost she simply cannot ignore: Aizawa Honami, her former classmate and a former member of the wildly popular idol group De:LPhinus. Honami has remained in their classroom as a lingering spirit, bound by some unresolved attachment. Despite Michi's determination to keep her distance from all spirits, Honami's childish, outrageous behavior and over-the-top, one-sided fan service keep drawing Michi's attention against her will.

The central conflict revolves around Michi's struggle to maintain her emotional walls while slowly becoming entangled with Honami, a ghost who refuses to fade away quietly. The setting is primarily a modern Japanese high school, where the mundane routines of student life are constantly interrupted by the supernatural, often in comedic and unsettling ways. As the story progresses, the initial comedic dynamic deepens into a mystery. Strange marks appear on Michi's neck, matching symbols found on Honami's desk, and Michi begins to realize she has no memory of a summer festival and, more crucially, no memory of having known Honami while she was alive. A spiritual medium named Karasuma Neo is called in to deal with the haunting and hints at a prior connection between herself and Michi. Meanwhile, other former members of De:LPhinus begin experiencing strange incidents linked to the possibility that the idol group once had a fifth, hidden member. The narrative balances laugh-out-loud supernatural comedy with genuine horror elements, all while building a quiet yuri romance between Michi and the ghost she is finding it harder and harder to pretend she cannot see.