Sonoyo No Dokoka, Chizu Ni Nai Kuni summary:

Intrepid traveler Shin has been to practically every country on the world map, except for the blank space around 500 kilometers away from his homeland. However, the moment he takes a single step forward, he’s immediately captured and told that anyone who comes to Oraie can never leave. As Shin carves out a place for himself in Oraie, he gets to know more about its young leader Musutia, who bears the responsibility for Oraie’s fate and future on his frail shoulders. He also meets Musutia’s beautiful retainer Noe, whose duties often entail giving Musutia a “healing kiss.” But is this just a ritual between master and servant? Or is there potential for it to blossom into anything more?