Isekai ni Ten'i Shitara Yama no Naka datta. Handou de Tsuyosa yori mo Kaitekisa o Erabimashita.

Story:

One summer day, Jin Konohana, is forced to carry luggage to a firework festival by his outrageous older sister, and before he knows, he finds himself in an unfamiliar mountain. In the mountains where no one is around, Jin begins a life of survival all by himself. In order to survive... I want to throw away all the troublesome things and live peacefully and comfortably! A slow life in another world that begins in the mountains!