I'm still working on the logline for the Ghost Builders, but since I'm basing it on the Orpheus and Eurydice myth I decided to write a logline for that:

After his wife dies during an attempted rape, a renowned musician must overcome the ruler of the underworld to bring his wife back to the land of the living.

It's a bit rough, but I think I'm getting the idea. I found this article on loglines to be very helpful.