This is a sequel from Cupcakes.

Four months after Pinkie's escape from prison, Ponyville is still in panic. The winged ponies fill the skies, looking for any intruders, while the new matyor sends protections and gruards to the Ponyvillians. While Rainbow Dash was peacefully guarding the skies, she came up upon a stranger, an old friend of Pinkie Pie. Even though all ponies admired that mare and she seemed so harmless, that mysterious mare has deadly secrets and lies that will show to the mane 6 that their bloody adventure isn't over yet...