5 years ago, Marble Pie's heart was broken when she discovered that Big Mac had chosen another mare. Over the years, she learned to accept it, and move on, but the pain was to much when her sister comes to the farm to announce she had a foal. Pinkie Pie, however, notices something is wrong when her normally shy and reserved sister suddenly snapped and yelled at her. Instead of shying away, Pinkie tries to help her sister by finding her soulmate!