In the twilight hour between night and day, somepony has to be on guard. Taken from both the Night and Day Guard, these ponies are known, unofficially, as the 'Overlappers'. Tonight, two ponies are finding they have been put on this patrol for a reason, and neither know why or by whom.

This is a sequel to 'Servant in the Dark', but does not assume much or any knowledge of the previous story. The important sections are explained in the story.