Wakana Gojo is a high school student who dreams of becoming a kashirashi for hina dolls one day. Because his life is all about making hina dolls, he has a hard time fitting into his class because his interests are so different than anyone else’s. His classmate, Marin Kitagawa, is always at the center of attention and from another world. One day, they both end up on classroom cleaning duty and…

After seeing how passionate Marin is about the things she loves, Wakana decides to help her with making outfits. He decides to help her out in making a cosplay for Shizuku Kuroe-tan from the game "Slippery Girls 2." They had planned to reconvene later to get the measurements started, but Marin couldn't wait and ends up coming to Wakana's house over the weekend.

Wakana finally completes the Shizuku cosplay. Marin is super excited that she gets to dress as her beloved Shizuku-tan and suggests that the two of them go to a cosplay event the next day. Even though it's her first time at a cosplay event, Marin gets requests for photos left and right. Wakana is overwhelmed with feelings as he watches over Marin, but...

Marin and Wakana have a successful first cosplay event. Because of something Wakana said, Marin's mental and emotional state starts to change a little. Even though she was just spending time at the Gojos' home with Wakana and Kaoru to wash her outfit, she can't seem to calm down. Meanwhile, a certain person comes to Gojo Dolls after seeing the photos Marin posted onto social media of her Shizuku cosplay.

Marin is going to do a group cosplay with her idol, the cosplayer "Juju," whose real name is Sajuna Inui, and they're going to cosplay as Black Lobelia and Black Lily from the magical girl anime "Flower Girl Blaze!!". Wakana heads over to Marin's home so that he can borrow the "Blaze!!" DVDs for research to make the outfits for them.