A mysterious killer known as the Black Widow has been targeting husbands who abuse their wives. Seen as a hero by some and a horrible criminal by others, the Black Widow's most recent killing has caused a lot of stir in Ponyville. While investigating Private and Twilight get into an argument over the situation. To solve this, Cadence casts a spell on the pair of them that suddenly transforms them into Dusk Shine and Pruena Oculia. While learning how the other gender lives the pair have to get used to their new bodies before the Black Widow claims her next victim.