After leaving her idol career behind, Fuuka Miyazawa finds herself on a spontaneous flight to Okinawa instead of returning home to her pity party in Morioka. Bearing a heavy heart and nowhere to go, she aimlessly wanders around the area until she stumbles upon Gama Gama Aquarium—an aging aquarium on the verge of closing down. With a lack of visitors and costly but necessary repairs needed to keep its doors open, the director is faced with shutting down the establishment for good by the end of the summer. The director's aquatic life-loving granddaughter—Kukuru Misakino—cannot stand the thought of the aquarium closing and is determined to make enough money by the end of the season to keep the doors open. Seeing the unique magic of the aquarium, Fuuka begs Kukuru for a job; however, she soon finds that her lack of experience makes her more of a hindrance than anything else. At the same time, Kukuru realizes that her ambitious goal might be more than she can handle. With mounting pressure from all around them, will Kukuru and Fuuka be able to save the one place they hold close to their hearts?

Mini Ika-Musume side-story episodes.

Shippuu! Iron Leaguer OVA.

Humans have been polluting the ocean for a long time, carelessly pouring their garbage and desecrating the waters that many creatures call home. The denizens of the sea have suffered at their poisoning hands. Finally, one certain squid has had enough and vows to punish the humans' selfish actions. Possessing all the fearsome abilities of a squid such as powerful hair-tentacles, the ability to spit ink, and even use bioluminescence at will, Ika Musume takes it upon herself to rise from the depths of the ocean and exact revenge upon humanity! She surfaces at a certain Lemon Beach House, a restaurant managed by the sisters Eiko and Chizuru Aizawa. Thinking them to be an easy first step toward world domination, she immediately declares war against them, only to find out that she is, quite literally, a fish out of water! To make things worse, she destroys a part of a wall of the beach house in an attempt to flaunt her squiddy superiority and is consequently forced into becoming a waitress to pay the repair costs. Beached for the time being after tasting a thorough defeat at the hands of the Aizawa sisters, Ika Musume is forced to put her plans for world domination on hold. Despite these setbacks, Ika Musume soon finds herself right at home in her unexpected position as Lemon Beach House's newest employee. Wacky and hilarious, Shinryaku! Ika Musume follows her brand new life on the surface as she makes precious memories and meet lots of new people. With her newfound acquaintances, Ika Musume is looking to take the world by storm, one squid ink spaghetti at a time!