Neo-Venezia has reached a long winter. Ai, Azusa and Anya, who were practicing jointly in the cold weather, visit the Undine Museum, led by Akira who seems not her usual self. At the museum, the trio meet its director, Asuka who is Akira's senior known as Himeya's legendary undine. The two of them are the successors to a gondola that has been carefully passed down sin...