Ellis, a young girl suspected of murdering a prominent physicist Heinrich Schneider, is on the run from an underground society called "Hunters" when she is tracked down by the bounty hunter Nadie in a small Mexican town. However, instead of turning her in, Nadie impulsively decides to help her and the two girls embark on a journey to Ellis' hometown, where they plan on finding clues about her past. From there, they travel south to search for the mysterious Gemstone of the Inca Rose, the "Eternal City" of Wiñay Marka, and Ellis' own obscure destiny.

(Source: Anime News Network)