Reincarnated As Lunatic Girl

A was an ordinary middle-aged man living a mundane life. Suddenly, he finds himself reincarnated as a young girl — alone and confused inside the dark hollow of a mysterious black tree, right in the middle of a vast, endless grassland. With no memories of how he got there and no one around, he must now navigate this strange new world in an unfamiliar young girl's body. What secrets does this grassland hide? How did this reincarnation happen? And what awaits him in this new life?