"Akikan!" is a manga series that blends comedy, romance, and science fiction, centering on the concept of anthropomorphic beverage cans. The story revolves around Kakeru Daichi, a high school student who becomes involved in a bizarre experiment where aluminum beverage cans are transformed into human-like beings called Akikans. These Akikans are designed to test whether steel or aluminum cans are superior, with each Akikan possessing a unique personality and abilities tied to their beverage type.

The narrative begins when Kakeru purchases a melon soda can, which transforms into a spirited and strong-willed girl named Melon. As an Akikan, Melon requires regular carbon dioxide to survive, which she obtains by kissing Kakeru. This dynamic creates a comedic and often awkward relationship between the two. The experiment escalates as other Akikans, such as Yell, a shy and gentle ginger ale can, and Budoko, a mischievous and competitive beer can, enter the fray. Each Akikan is paired with a human partner, and they engage in battles to prove the superiority of their respective can materials.

The plot explores the growing bonds between the Akikans and their human partners, as well as the ethical implications of the experiment. Kakeru and Melon navigate their evolving relationship while facing challenges from rival Akikans and the shadowy organization behind the experiment. The series balances lighthearted humor with moments of emotional depth, particularly as the Akikans grapple with their purpose and humanity. The story also delves into themes of identity, companionship, and the consequences of scientific experimentation, all while maintaining a playful and whimsical tone.