A science fiction anime series about flying trains set in the far reaches of space.

Set in the early 24th century against the backdrop of the city of Neo Venezia on the planet Mars. No longer the barren red planet, Mars has been flooded, inhabited and is something of a tourist hub for those looking for rest, relaxation and a gondola ride – the primary mode of travel in Neo Venezia. The Undines are professional gondoliers, tour guides for the people passing through. Akari Mizunashi is an Undine in training and this is a piece of her story.