On the eve of Twilight's wedding, trouble is brewing. Fluttershy mourns the love she lost and contemplates the bitter dregs of hate. Two friends loved the same stallion and he chose one. As mysterious murders rock the city of Canterlot and an ancient evil returns to battles long abandoned, Twilight and Fluttershy will finally have that peculiar heart to heart that only rivals in love can have.
Unrequited passion is a dangerous force. In normal circumstances, a controllable one. When two mares who loved the same pony are left alone in the dark? Perhaps a lethal one.
(EDITED by the Illustrious RazedRainbow, the better craftsman. )