Simply dumping more waste into the water has an impact on its residents' quality of life. Ika Musume, a squid girl who lives in the water, decides that she can take no more of this and takes it upon herself to conquer humans in retaliation. Ika's conquering campaign comes to an end, however, at the nearby beach café, where the proprietors order her to pay for the damage after she willfully destroyed a side wall. Ika is taken aback by the land dwellers' skills and their resistance to her attempts at conquest, but she persists and keeps working covertly on strategies to carry out her plan.
