trying to find out what this means

[andy.s]

ok im currently trying to read a light novel so im studying and spending 1 hour a day trying to read well i got this sentence and i cant figure out what this means please help spend 30 minutes trying to find what works i got the gist of it till here 薄闇が　(下り)　室内に thats where i got lost i tried to find any kanji compounds that worked or a meaning any help is apreciated

[community.japanese]

andy.s san,
konnichiwa.

薄：light and it means dim here
闇：Darkness
室内：Indoors
A room becomes dark (dim).

Yuki　由紀
Team JapanesePod101.com

[richard_j.hughes_510244]

It means The darkness is (down) in the room

[community.japanese]

san,
konnichiwa.
Thank you for your post.
Team JapanesePod101.com
Yuki 　由紀