This story is a sequel to The Twilight Before the Sunset
There is one month left until Sunset Shimmer's birthday. One month until Princess Celestia must confess that they are family. Luna and Twilight are anxious to hear Sunset's response when she hears about who her mother is, but Twilight is burdened with the duty to persuade Sunset to visit Equestria and Luna must try to reassure her sister that everything will be fine. The odds of her coming are slim, but they're determined to bring Sunset Shimmer back with her mother, to reunite mother and daughter.
That is, if Sunset will accept the truth.