"Kaijū Girls Kuro: Ultra Kaijū Gijinka Keikaku" is a short-form anime series that reimagines classic Ultraman kaiju as anthropomorphized girls, blending elements of comedy, action, and slice-of-life. The story centers on a group of kaiju girls who live in a world where they coexist with humans. These girls are personifications of iconic kaiju from the Ultraman franchise, now transformed into humanoid forms with distinct personalities and abilities tied to their original monster counterparts.

The protagonist, Red King, is a cheerful and energetic kaiju girl who aspires to become a hero. Alongside her are other kaiju girls, including Eleking, a reserved and intelligent character, and Gomora, who is strong-willed but often struggles with her emotions. Together, they navigate their daily lives, balancing their kaiju heritage with their human-like experiences. The series explores their interactions with each other and the humans around them, often highlighting humorous or lighthearted situations.

A recurring element of the plot involves the kaiju girls facing challenges that test their abilities and teamwork. These challenges often stem from their attempts to prove themselves as capable individuals, despite their monstrous origins. The series also incorporates references to the original Ultraman series, with nods to the kaiju's iconic traits and battles. While the tone is primarily comedic, there are moments of character growth and introspection as the girls grapple with their identities and purpose in a world that views them as both fascinating and unusual.

The narrative structure is episodic, with each episode focusing on a specific kaiju girl or a group dynamic. This format allows for a variety of scenarios, ranging from school life to action-oriented sequences where the girls confront threats or misunderstandings. The series maintains a lighthearted approach, emphasizing the quirky and endearing qualities of its characters while paying homage to the legacy of the Ultraman franchise.