The story is there, but the main focus of Ingrid is the monster sex so once the initial setting of the story is established, it’s non-stop sex.
This approach is a good thing if you just want to a modern tentacle and monster sex hentai anime.
This is not exactly a happy story, but the hentai was nice enough to give the “hero” a sufficient backstory and a reason why he wants to exact revenge on his father.
Throughout the series, our nameless hero first raped his half-sisters and then proceeded to literally rape everyone in the school.
Minase found a book of magic in his school and after reading the pages, the magic contained strong sexual effects which Minase used to his advantage.