"Dantalian no Shoka: Ibara-Hime" is an OVA adaptation of the light novel series "Dantalian no Shoka," written by Gakuto Mikumo. The story is set in post-World War I England and centers on Huey, a young man who inherits a mysterious library from his late grandfather. The library, known as the Bibliotheca Mystica de Dantalian, contains forbidden books called Phantom Books, which hold dangerous powers. Alongside the library, Huey inherits the responsibility of its guardian, Dalian, a girl with the ability to unlock and control the Phantom Books.

The narrative begins with Huey arriving at his grandfather's estate, where he encounters Dalian, who resides within the library. She explains her role as the "Keykeeper" and the nature of the Phantom Books, which can unleash chaos if misused. Together, Huey and Dalian form a partnership to retrieve and seal away rogue Phantom Books, ensuring they do not fall into the wrong hands. Their mission intertwines with themes of mystery, supernatural phenomena, and the consequences of human desire.

The OVA focuses on a specific story arc involving a cursed Phantom Book tied to a tragic tale of love and betrayal. The plot delves into the history of a noble family and the legend of a princess known as the "Ibara-Hime" (Thorn Princess), whose story is linked to the cursed book. As Huey and Dalian investigate, they uncover the dark secrets surrounding the book and its connection to the family's downfall. The narrative explores themes of obsession, sacrifice, and the blurred line between reality and fiction.

Huey is portrayed as a pragmatic and resourceful individual, balancing his newfound responsibilities with his own moral compass. Dalian, on the other hand, is enigmatic and aloof, often providing cryptic insights into the nature of the Phantom Books. Their dynamic is central to the story, blending elements of partnership and mutual dependence as they navigate the dangers posed by the books.

The OVA maintains a gothic atmosphere, with its historical setting and supernatural elements creating a sense of intrigue and tension. The story is self-contained, offering a glimpse into the larger world of the "Dantalian no Shoka" series while focusing on a single, impactful narrative. The interplay between the characters and the exploration of the Phantom Books' lore provide a compelling foundation for the series' overarching themes.