The Mermaid Line is a compilation of short mini-series that appeared in Yuri Hime magazine, adopting an episodic and soap-opera-like approach. "Megumi and Aoi" centers around Megumi's confession to her friend Aoi that she feels like a mermaid despite struggling with swimming. Aoi begins to daydream about being Megumi's prince, but Megumi opts for a boy, masking her emotions. In "Ayumi and Aika," Ayumi desires to tie the knot with her boyfriend, but is stunned to discover that he plans to transition into a woman. "Yukari and Mayuko" involves two office ladies, with Mayuko seeking Yukari's assistance by pretending to be her romantic partner. However, Yukari realizes her emotions extend beyond make-believe. Lastly, "Miura-san and Me" showcases Okabe's admiration for Miura's hair, which dissipates after Miura-san trims it all off, compelling Okabe to appreciate Miura for who she is.
