"Baka and Test: Summon the Beasts OVA" is a self-contained episode that expands on the comedic and competitive dynamics of the original series. The narrative revolves around Akihisa Yoshii, the protagonist, and his classmates in Class F, the lowest-ranked class at Fumizuki Academy. The school employs a unique system where students can summon avatars, or "Summoned Beasts," whose strength is determined by the academic performance of their summoners. These avatars are used in battles between classes to compete for better facilities and resources.

In the OVA, the story begins with Akihisa and his friends preparing for a school festival. However, their plans take an unexpected turn when they discover a mysterious, cursed DVD that supposedly grants any wish to those who watch it. Intrigued, the group decides to watch the DVD, only to find themselves trapped in a bizarre, alternate reality where their roles and personalities are drastically altered. Akihisa becomes a genius, while the typically intelligent Hideyoshi Kinoshita and Yuuji Sakamoto are reduced to bumbling fools. The once timid Minami Shimada transforms into a bold and assertive character, and the usually composed Mizuki Himeji becomes overly emotional.

As the characters navigate this strange world, they must confront exaggerated versions of their own insecurities and flaws, all while trying to find a way to return to their original reality. The OVA maintains the series' signature blend of slapstick humor, witty dialogue, and over-the-top scenarios, with the characters' interactions driving much of the comedy. The episode also explores the relationships between the main cast, particularly the evolving dynamics between Akihisa, Minami, and Mizuki, adding depth to their personalities.

The OVA concludes with the characters managing to break free from the cursed DVD's influence, returning to their normal selves. The resolution reinforces the themes of friendship and self-acceptance, as the characters reflect on their experiences and reaffirm their bonds. While the OVA does not significantly advance the overarching plot of the main series, it serves as an entertaining and lighthearted addition that complements the established tone and character dynamics of "Baka and Test: Summon the Beasts."