After recovering her squid-like powers, Ika Musume is back on track to fulfill her goal of eradicating mankind. Nevertheless, her lackadaisical occupation at the Lemon beach house impedes her progress, as she squanders her idle moments lounging around. Moreover, she grapples with challenges such as evading a group of extraterrestrial enthusiasts and garnering the interest of a peculiar girl. Picking up from the previous season, Shinryaku!? Ika Musume illuminates the amusing existence of Ika Musume as she formulates a new plot to subjugate humanity.