Темнота в коридоре мешает мне найти выход.

The darkness in the corridor prevents me from finding the exit.

Breakdown of Темнота в коридоре мешает мне найти выход.

• в: in
• мне: me
• найти: to find
• выход: the exit

Questions & Answers about Темнота в коридоре мешает мне найти выход.

Why is темнота (a noun) used instead of темно (an adverb/state word)?

Темнота means darkness as a thing/phenomenon and can be the grammatical subject of a sentence: Темнота … мешает = The darkness … prevents/hinders.
Темно means it’s dark (a state) and is used in impersonal sentences, e.g. В коридоре темно. = It’s dark in the corridor.
Both are natural, but they build different sentence types.

What case is в коридоре, and why?

В коридоре is prepositional case (locative meaning) because в + prepositional typically answers where? (где?) when talking about location:

• в коридоре = in the corridor (location)
  If it were motion “into,” you’d usually get в + accusative: в коридор (direction).

Why is it мешает мне—what case is мне, and what does мешать govern?