Emma Winberry is a supernumerary (extra) in the opera. A stranger is lurking in the opera house, but only a few people can see him, Emma included. She and her significant other, Nate Sandler, find information that dates the original site back to the time of the Underground Railroad. Is this entity an earthbound spirit? How does Emma help him to cross over? To add to the mystery, a figure in black is leaving packages in a hidden niche. What is the significance and how does Emma solve the mysteries?