Under the light of the full moon, the Ninja Turtles patrolled the streets of New York, leaping from building to building with agility and precision. The city was quiet, but the brothers knew there was always something lurking in the shadows. From a distance, they could see their human friend on the rooftop of a nearby building. She was devouring something with disturbing ferocity.

Michelangelo, normally the most carefree, felt a chill run through his body. “That’s not normal, guys. Something’s not right.”

The figure on the rooftop raised its head, and the four brothers froze. Its eyes were bloodshot, and sharp fangs protruded from its mouth. But the scariest thing was the black veins that spread across its skin.

“Watch out!” Leonardo shouted, just as she launched herself at them with supernatural speed.

Leonardo brandished his katanas, Raphael his sais, Donatello his Bō staff, and Michelangelo his nunchakus. But she was faster, fiercer. Her nails, now long and sharp, moved with a savage violence.

Leonardo, with the calm of a leader, moved behind her in an attempt to control her. With a quick movement, he placed one of his katanas between her fangs, trying to hold her back. But she struggled, desperately reaching out her hands to scratch whoever was closest, while a guttural growl came from her throat.

“Calm down! We don’t want to hurt you!” Leonardo exclaimed, struggling to maintain control, but the uncontrollable fury of his human friend made them fear the worst.

The Ninja Turtles managed to knock out their friend after an intense fight, but not before she scratched Leonardo, leaving a deep wound. They immediately took her to the lair and chained her in Donatello's laboratory, where he worked tirelessly to find a cure. They were unaware that in the meantime, the parasite had begun to grow in Leonardo's wound.