Care To Squidertain Our Guests?! Ink That Amnesia?! You Porpoise Joining The Club?!

Ayumi's father invites the Aizawas to have dinner at his house, where Squid Girl and Eiko find his unique hospitality to be quite awkward. Later, Squid Girl falls down the stairs and loses her memory. As the others try to make up memories for her, she regains them after she tries to force her hat off and sees her life flash before her eyes. Later, Squid Girl decides to set up an 'Invasion Club' with Kiyomi and her friends, where they go out to various places to 'invade'. Squid Girl becomes worried about the club when Kiyomi becomes absent with a cold, but they all decide to visit her and invade her house too.