Twilight Sparkle made a huge mistake and created a fungus which infects Ponies. Whole Equestria is in danger, and she needs Sunset Shimmer's help! It has been 3 weeks now in the outbreak, Sunset has finally got the message and got prepared and went through the hidden portal in the human world and comes back as a unicorn in the realm of Equestria.

As Sunset entered, she knew in an instant, something was wrong: She felt an awful presence around Twilight's Castle.

Sunset: "Twilight, is everything okay?" She says as she wanders around the castle while speaking in her mind "((This castle has never felt so empty and creepy before... where is she?))" She keeps looking around while calling out for Twilight "Twilight...? Please, say something!"

Still, no one answered. Sunset then went to the basement level of the castle while being worried

Sunset: "Twilight please, i'm worried... Twili--" She stops as she sees a horrific sight with tears forming in her eyes

Sunset saw a dead and bloody spike on the floor with black roots coming out of his body and she saw Twilight with her head down, her hooves being bloody.

Twilight: Very guilty of her chilling violence on spike "I'm so sorry Sunset... I can't help it..."

Sunset: Is horrified but steps closer "Twilight... please, let me help--"

Twilight: Sobbing while avoiding Sunset "NO! You have to run!... Find Princess Luna and Celestia!!"

Sunset: Worried and tries to see Twilight's face "Let me just help you-"

Twilight: Lifted her head up, her face was messed up and bloody. Her left eye was gone and black roots were coming out of it "I SAID RUN!"

Sunset ran out of the castle, far away from Twilight as much as possible while being heartbroken. Sunset made it to Ponyville and met up with Trixie and Starlight after saving them from an infected and explained what she knows

Sunset: Looks down "Twilight... is also infected and killed spike."

Trixie: Shocked as hell and angered "SHE FUCKING WHAT?! Does this fungus make ponies turn into hungry brutal monsters?!"

Starlight: Looks up at the dark gloomy sky "This is where it all ends, huh...?" She said, sounding hopeless until...

???: Worried and hurt "Somepony?! Anypony there?!" They yell, waiting to find anypony

The 3 looked for where the voice was coming from and when they found who owned the voice, it was Rarity... she had open cuts and her eye sockets were empty and bloody!

Rarity: Worried while brutally blind "H-Help! i can't see!"

Sunset: Walked to Rarity with a soft expression "Rarity, it's just me, Trixie, and Starlight.."

Starlight: Walks around Rarity, taking in her brutally scarred appearance "You look awful..."

Trixie: She felt VERY bad for Rarity, but one thing was on her mind "Rarity... How come you aren't infected yet? You have cuts all over you..."

Rarity: Looking around "I- i don't know... But, what's going on in ponyville?!"