Second season of Hiiro no Kakera.

Nearly twenty years into the 21st century, people have forgotten the existence of youkai. When a number of unexplainable phenomena plague adults of the human world with confusion and chaos, thirteen-year-old Mana writes a letter to the Youkai Post in search of answers, only to be greeted by Gegege no Kitarou...

Nadie is a bounty hunter with an attitude, and she's got a lock on her next target: Ellis, a young amnesiac girl who is a suspect in the murder of a famous scientist. Nadie manages to apprehend Ellis, but on a whim, decides to accompany her to Wiñay Marka, a place which supposedly holds the key to unlocking Ellis's memories and her mysterious past. However, Nadie cautions Ellis that this does not mean she will go free—once Ellis has found what she is looking for, Nadie will turn her over to the authorities. With Ellis's connection to a gemstone called the Inca Rose as their only guide, the two set off on their journey south through Mexico to search for the mysterious "Eternal City" of Wiñay Marka.

With broken spirits and enigmatic questions that hold no answers lingering, Jil is still trying to figure everything out. Then, a mysterious girl named Kai appears before him and says: "Take me to the top of the tower." Kai's request shrouded in ambiguity, Jil will have another chance to work towards completing his destiny and ascend the Tower. With his hopes and aspirations seemingly slipping out of his hands, Jil must rise to the challenge once again on this never-ending adventure. (Source: Crunchyroll)