This is a series of OVAs covering some of the Magic World manga arc by Ken Akamatsu, starting with chapters 184 through 188.

The world as we know it is actually just half the story, as Takeshi Nanase finds out abruptly one summer morning. On his way to kendo practice, Takeshi comes across an unconscious girl in a uniform he doesn't recognize. Takeshi does the decent thing and saves her, and in return the girl wakes up and accidentally turns him into a magic-user. As Takeshi finds out, there is the world he lives in and the world of magic users. Most magic users just want to peacefully coexist with non-magicians, but there are some with bigger ambitions. Mui Aiba is a magician enrolled in the Subaru Magic Academy, where magic users can learn to control and channel their powers and how to live in peace with regular humans. After his fateful encounter with Mui, Takeshi and his newly magician friends Kurumi Isoshima and Kazumi Ida decide to enroll in the Magic Academy as well. All three friends have different reasons for fighting on, whether they're fighting to escape the past or catch up to the future. They wield different kinds of powers, which they must learn to harness in order to fight off the Ghost Trailers, a group of magicians who are willing to use violence to assert their superiority over humans. Pursued by the Ghost Trailers, Takeshi and his friends must train to become stronger, face the leader of the Trailers, and prevent the beginning of the Second Great Magic War.

Before the beginning of the series, three OVAs were produced for the sole purpose of introducing the characters. The first two were released on DVD bundled with two drama CDs, with the third being sold separately. It is unknown if these will ever be released outside of Japan. The first OVA is a re-enactment of the first chapter, where Negi first learns of his job as a teacher and is introduced to the students of Mahora Academy 2-A. It ends with profiles of the Baka Rangers (Asuna, Makie, Yue, Ku Fei and Kaede) as well as Ayaka. Asuna is the only girl in the class that doesn't have romantic feelings for Negi. The second OVA is a re-enactment of the love potion incident of chapter 2, with profiles at the end of Nodoka, Konoka, the cheerleaders (Misa, Madoka, Sakurako) as well as Kazumi. The third OVA is a re-enactment of chapter 13: Negi's Mahora tour with the Narutaki twins. The tour shows Negi to several of the students (Yuna, Akira, Chao, Satsuki, Satomi, Chizuru, Natsumi, Zazie) as well as others that he ends up missing (Sayo, Evangeline, Chachamaru, Chisame, Misora, Ako). After being chewed out by Haruna for completely skipping her, a final scene introduces Setsuna and Mana, keeping watch from something on campus. (Source: Wikipedia)

During a rash attempt to save her father and her dying home planet of Eltria, Kyrie Florian is betrayed by her childhood friend, Iris. Furthermore, the power Kyrie has gathered from Nanoha Takamachi and the other Earth protectors cannot be used to help her father. Iris casts the despairing Kyrie aside, having acquired what she desired to exact revenge on Yuri Eberwein, a powerful being who lies dormant on Earth. Left to pick up the pieces, Nanoha and her allies must confront the troublesome Iris to uncover the truth and stop the conflict between her and Yuri. However, amidst the raging battles, a much more dangerous threat lingers in the shadows. No matter the obstacle, Nanoha remains diligent and does not hesitate to help those in need with her magic.