Today is Planeptune's Cosplay Party! Our host Neptune is completely womped from party preparations. Neptune then finds out that Older Neptune, whom she met in the mountains during her summer vacation, was arriving to this dimension. Nepgear and friends decide to leave Neptune while she finishes preparing for the party, and pick up Older Neptune. However, when Nepgear and friends returned, they found Neptune completely burned out!

[Source: Idea Factory via Steam]