So I have been experimenting with Daz3D's sunlight/daytime settings lately. One thing you can do there is simply specify the place and time and let it calculate the sun position etc. automatically for you. It does not seem to do any moonlight or starlight, but daylight from the sun and sky works perfectly.
And I know some people are going to say that this image is too dark, but that's OK. After all our mystery sinker stumbled into this mess
because it was getting dark. You may have to look closely and let your eyes (and possibly contrast/brightness settings) adjust to it to even see that someone's there. Once you see the silhouette let your imagination do the rest.

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