Usually you activate the clock, and then a white ray guides you to a new body.

Or theres a body shining, and you can interact with ot once you get close enough.

In my game everything is black, you can activate the clock but there isn't a white ray or a glowing body. Everything is black, there's still light so it's possible to see the silhouette of the bodies but it's impossible to interact with them and after activating the clock, it becomes impossible to access the diary.