"Robot Girls Z+" is a short-form anime series that reimagines classic mecha characters from the "Mazinger Z" franchise as anthropomorphic, energetic schoolgirls. The story is set in a world where these robot girls, known as the "Robot Girls Z," attend school and protect their city from various threats, primarily the Mechanical Beast Girls, who are also anthropomorphic versions of the original series' antagonists. The narrative blends slice-of-life elements with action-packed sequences, creating a lighthearted and comedic tone.

The main trio consists of Z-chan, Gre-chan, and Grenda-chan, who are personifications of Mazinger Z, Great Mazinger, and Grendizer, respectively. Z-chan is the cheerful and somewhat clumsy leader, Gre-chan is the serious and disciplined member, and Grenda-chan is the gentle and kind-hearted one. Together, they form a team dedicated to defending their city from the Mechanical Beast Girls, who are led by the enigmatic Dr. Hell and his assistant, Baron Ashura. The Mechanical Beast Girls frequently attack the city, leading to battles that are both humorous and action-oriented, often parodying the original series' dramatic tone.

The series incorporates episodic storytelling, with each episode featuring a new challenge or threat from the Mechanical Beast Girls. The battles are resolved through teamwork and clever strategies, often with comedic twists. The interactions between the Robot Girls and their adversaries are playful, with the Mechanical Beast Girls often displaying quirky personalities that contrast with their destructive intentions. The show also includes moments of camaraderie and school life, highlighting the friendships and rivalries among the characters.

"Robot Girls Z+" maintains a light and comedic approach throughout, with its focus on parodying the original "Mazinger Z" series while introducing new, humorous dynamics. The series does not delve deeply into complex plotlines or character development, instead prioritizing entertainment and homage to the classic mecha genre. The characters' designs and personalities are directly inspired by their original counterparts, creating a nostalgic yet fresh take on the source material. The anime's brevity and episodic structure make it accessible and easy to follow, appealing to both fans of the original series and newcomers.