In the end, what is the "the light in the heart" that the ghosts are looking for?An example of what it signifies is fine.
The narrator describes the joy of being in love as a " light in the heart". It's obvious the two ghosts were very much in love when they lived in the house where the narrator and her husband now reside. As ghosts, the couple can no longer feel the joy and other emotions that loving another person can bring, and they want to recapture those feelings. That is what the ghosts are looking for; they want to experience again those feelings and cannot since they are no longer human. The narrator and the two ghosts realize that what the ghosts have been searching for lies within the narrator, in the love that she has for her husband.