People become afflicted by "mysterious diseases" when their hearts and minds are affected by "the mysterious." Koto, a girl who produces mayonnaise from her eyes, visits Dr. Ramune, who specializes in these diseases that can't be explained by modern medicine. She was brought to the clinic by Ramune's apprentice Kuro. Koto explains that she also cries condiments other than mayonnaise, and Ramune offers her a mysterious treatment.