Kanna starts living with Tohru and Miss Kobayashi. While the livelier residence is nice, sharing a tiny apartment with three people becomes cramped. So Miss Kobayashi decides to move. She winds up inviting Takiya to her new apartment for a party, but Tohru also invites her dragon friends, Fafnir, who lives in a cave, and Lucoa, who's lived in this world since ancient times, to visit their new home.

Miss Kobayashi and the others go to the beach. But Lucoa's immediately dragged off by one of the lifeguards for her overly skimpy swimsuit. After regrouping, they put sunscreen on each other, split a watermelon, go swimming together, and enjoy summer to the fullest. After the beach, it's comiket! Tohru and Miss Kobayashi both head for the otaku's battlefield, and even Tohru gets shivers from the incredible aura surrounding those otaku. While helping Takiya with his circle, Tohru's horns and wings are mistaken as cosplay?!

It's Kanna's sports festival. However, when she learns Miss Kobayashi is too busy at work to come, she sulks. Miss Kobayashi wonders why she'd want her to come so badly when she isn't Kanna's parent, but Kanna already views her as one. Even Takiya tells her, "You should decide based on if you want to go, not if you can go." Finally, the day of the sports festival arrives. As a dragon, Kanna should have overwhelming physical prowess, but...?!