Ika Musume has come out of her home in the ocean on a quest to punish humanity for polluting her waters. With squid tentacles for hair and some pretty useful ink-spitting skills, Ika Musume is sure she'll have no trouble invading Earth. What she didn't account for were the Aizawa sisters, rough and tumble Eiko and deceptively mellow Chizuru, who immediately bully her into working as a waitress in their seafood restaurant by the shore.