The successor and branch manager of the Himeya Company—one of the many Undine associations housing female gondoliers—Aika S. Granzchesta surprises everyone when she rejects tradition and refuses to inherit the company's legendary gondola. Aika's apprentice Azusa B. McLaren, unable to wrap her mind around her mentor's unexpected decision, confronts her directly but to little effect. To better understand her reasoning, Azusa and her fellow Undines secretly plan to arrange a meeting with Aika.

With the much-awaited winter days in sight, accompanied by the tranquility and sublimity of Neo-Venezia, Aika reminisces about her journey as an Undine that forged her into the person she is today. As she vividly remembers all those invaluable experiences of the past, she trusts they will continue to guide her into the unknown yet boundless future.