The game is flexible to an extreme extent. You can let Nai work to earn money, go out for fun to strengthen your bond with her or learn all sorts of things.
"Please protect me... Please get me out of here..." Spike was taken to a concentration camp where he met Anna, the goddess he had loved for years, only to find out she was being ab*sed every night in the cell next to his.
Kyosuke and his fiancée, Erisa, are visiting an isolated island in the sea and attending a mysterious festival to make a sacrifice to the island's gods. It should have been a romantic holiday, but the island seemed to be overshadowed by a great fear coming from the abyss...