Mika calls Yūto late at night to invite him to Haruka's birthday party on the evening of October 20. On the day of the celebration, Yūto goes to Akihabara to buy a gift and bumps into Nobunaga. After buying the gift, Yūto goes home and is fetched by Hazuki and Nanami to be taken to the party venue on an island far away together with Ruko and Yukari. On the island, Yūto meets up with Mika and Haruka. After meeting some of the guests, Yūto starts feeling insecure about his gift and social status.