read the book, the movie is terrible! but the story is that there's this french peasant and the angel teaches him how to make wine, but he only comes to see him once a year. eventually the vintner falls in love with the angel, and the angel freaks out and tells him that he's actually a fallen angel, and that he's a contract between heaven and hell. and the angel has this little garden in hell where he brings roses from earth to it and eventually you meet lucifer and it's a PERFECT SETUP for the song, she even mentions "garden of evil".

but it'd be so fun to do a lukai story, luhan meeting a young trainee jongin, and jongin is convinced heaven has heard him, and when he debuts he tells luhan thank you, and luhan has to admit he's a fallen angel ;~; and jongin tells luhan he never wants to see him again and luhan doesn't for the entirety of jongin's idol career ;~; and luhan can find him again when jongin is older and burnt out