Choujigen Game Neptune THE ANIMATION: Nepu no Natsuyasumi

The first entry in the Neptune OVA series features Neptune and her companions traveling to a mountain setting for a summer vacation. The four goddesses reunite and enjoy each other's company. While exploring the area, Nepgear and her sisters pass through a long stretch of torii and enter another dimension. There, Nepgear encounters a woman resembling her sister Neptune in an adult form.