Akikan!

Kakeru Daichi purchases a can of Melon soda. When he goes home and drinks it, the can transforms into a girl. Thinking it's all a dream, Kakeru acts perverted in front of this girl, before getting attacked by the girl's powers. Kakeru ends up treating the can rather shoddily due to the conflict in behaviour and leaves her in a cupboard before going to school. When he comes back though, he finds the girl drained of all life due to being low on carbon dioxide, so he kisses her to allow her to live. Kakeru decides to name the girl Melon. They are visited by a man named Hidehiko Otoya who explains that the 'girlish' cans are part of a battle called 'The Akikan Elect' to determine whether steel cans or aluminium cans are superior. Kakeru is seemingly against this, as he doesn't want people to fight needlessly.

Kakeru notices that Melon doesn't do much during the day, and decides she should go to school with him, where he introduces her as her cousin. There is a bit of hostility between Melon and Kakeru's friend, Najima Tenkuji. When trying to find a place to put Melon back into a can, Kakeru enters a freezer room, and when Najima enters as well, they get locked in. During the cold, Najima recalls the time when Kakeru saved her from being kidnapped.

Kakeru and Melon are confronted a small aluminium Akikan named Budoko, whose powers come from her grape juice nature. She explains that Akikan types can be told by which ear a ringtab is on. While her primary attacks seem to have little effect on Melon besides annoyance, her explosive attacks are more dangerous. Melon gains the upper hand, but Kakeru breaks the fight up and Budoko escapes. Melon and Kakeru argue about their different standings on the Akikan Elect. After some talking, Kakeru decides they will participate in the Akikan Elect, but they will always try to avoid fighting if necessary. Afterwards, Kakeru, Yurika and Goro go over to Najima's house for a study session. While having a few drinks, Najima gets 'drunk' on carbonated drinks. When she goes to buy some more drinks, she drinks an energy drink which turns out to be an aluminium Akikan named Yell, stealing her first kiss.

Yell is left behind at the vending machine, while Najima has gone home, where during her still-drunkenness, she asks Kakeru on a date for the following Sunday. Meanwhile, Melon encounters Yell, where they discover they are both Akikans and start to fight, but they soon lose each other. The next day, Otoya and Kizaki arrive at Najima's house with Yell to explain the Akikan Elect. Both her and Kakeru are given scanners for detecting other Akikans, and Kakeru is informed that one of the owners goes to the same school as him. Najima tells Yell that she should go wherever she wanted, but she comes back wishing to stay with her owner, which Najima accepts.

Kakeru starts to become curious about where the Akikan owner is, while Najima notices the ringtab on Melon's ear. When she asks Kakeru concerning the date, she is told it would have to be postponed indefinitely. Later, Melon spots someone on a baseball game that looked similar to the Akikan she fought, and they go off to investigate, visiting an amusement park and a baseball game, where it turns out the girl in question was just a sports drink vendor. Najima spots the two together, and orders Yell to punish Kakeru. Yell then proceeds to slash her energy sword across his stomach.

Melon discovers Yell who had just harmed Kakeru with her sword. Before the battle could continue, Najima returns Yell to can form, apologises and runs off. Kakeru declines going to the hospital, since it would get Najima in trouble. Feeling responsible for his injuries, Melon decides to fight Yell on her own. Yell tries to console her owner, but Najima is still in shock. Melon arrives, tells Najima to go to Kakeru, and tells Yell to follow her to the baseball stadium where none would get hurt. When Kakeru becomes aware of the situation, he starts to head off to find them. Najima asks if he likes Melon, he said he thinks of both of them as his important friends, and wants to be friends with Yell too. Stuck in a traffic jam, they ask Goro to come by with his motorbike. When it almost crashes, Yurika appears as a fully fledged witch and carries them to safety. The fight between Melon and Yell had reached a critical point with both of them reaching their limits, but Kakeru stops the fight and tells everyone to get along.