"Akikan!" is a 12-episode anime series that blends comedy, romance, and light science fiction. The story centers around Kakeru Daichi, a high school student with a penchant for collecting aluminum cans. His life takes an unexpected turn when he opens a melon soda can that transforms into a humanoid girl named Melon. This transformation is the result of a mysterious experiment conducted by a group of scientists aiming to determine whether steel or aluminum cans are superior. The experiment involves turning certain cans into "Akikan"—anthropomorphic beings who must engage in battles to prove the dominance of their material.

Melon, as an aluminum Akikan, requires carbon dioxide to survive, which she obtains through kisses from Kakeru. This necessity creates a unique dynamic between the two, blending humor and awkwardness as Kakeru adjusts to his new reality. The plot thickens when other Akikan, such as Yell, a steel can transformed into a girl, enter the picture. Yell is paired with Kakeru's childhood friend, Najimi, and the two Akikan quickly become rivals, reflecting the broader competition between aluminum and steel cans.

As the series progresses, Kakeru finds himself caught in the middle of the Akikan battles, which are orchestrated by the scientists behind the experiment. These battles are not only physical but also emotional, as the Akikan develop their own personalities and relationships with their human partners. The narrative explores themes of identity, loyalty, and the bonds formed between humans and their anthropomorphic counterparts. The series maintains a lighthearted tone, often punctuated by comedic moments and romantic tension, while occasionally delving into the ethical implications of the experiment.

The main characters include Kakeru, who serves as the reluctant protagonist; Melon, the cheerful and somewhat naive aluminum Akikan; Yell, the competitive and headstrong steel Akikan; and Najimi, Kakeru's childhood friend who becomes Yell's partner. The supporting cast includes other Akikan and humans who contribute to the ongoing conflict and comedic situations. The series concludes with the resolution of the Akikan battles, though it leaves room for interpretation regarding the future of the experiment and the relationships formed throughout the story.