This story is mostly told from Seokjin's perspective. Jungkook's main arc is Infection.
This story is pretty dark and does have a lot of twist and turns. One of the main themes in their relationship is things that can seem like abuse - although neither of them see it as that.
There is some light, because Seokjin is the more 'normal' one of the two. The things he struggles with are issues that a lot of people have. Low self esteem and barely any self worth. That does begin to change during the course of the story, and because of that, he starts to question a lot of other things too.
All of this is real; one of the things I played with is it all being a dream.
Seokjin is actually not crazy, despite how much the way he feels like he might be, and that's one of the things I really wanted to explore.
I do not actually own BTS and I am 100% sure that neither Seokjin nor Jungkook are actually like this. Rumor has it that Seokjin is actually a real life sugar glider and you just feed him sweets and love him.