Liz is a succubus who appears in one of Marin's favorite slice of life series, "SuccIDK." Marin had some interest in cosplaying Liz-kyun but didn't think she could pull it off until Wakana gave her a little push. With the cosplay ready, they head to a studio for a photoshoot, but the studio happened to be a rather unexpected location.

Summer vacation is coming to a close. Wakana received an SOS from Marin, who hadn't finished her homework, so he ended up helping her study at her house. They later realize that Marin had forgotten some math drills at school, so they go to get them. While alone at the school, Marin and Wakana make plans to go to a summer festival together. And when that day finally arrived...