Ika Musume also known as Squid Girl in the English version is the main protagonist in Shinryaku! Ika Musume. Ika Musume, self proclaimed "Messenger of the Ocean", came from the sea to invade the surface world as revenge on humanity for polluting the sea, her home. She first attempted to "invade" Lemon, a beach house owned by the Aizawas. She was not taken seriously and was mistaken for a cosplayer. Ika Musume accidentally plunged a hole on the wall and was asked to work as a waitress by Eiko Aizawa for the cost of reparations. Ika Musume's invasion efforts are frequently foiled by a variety of circumstances, including being stopped by a mysteriously strong, Chizuru Aizawa, Eiko's sister.