"Mutant Hearts, Human Days" – A TMNT High School AU Storyline
It started with an accident.
Deep within the lair, Donatello was testing a prototype molecular destabilizer—designed to reverse the effects of mutagen on organic life. A promising invention. One that could potentially restore what had once been lost.
But then the Foot attacked.
In the chaos, the device was damaged. Sparks flew. Energy surged. And in the aftermath, the four Teenage Mutant Ninja Turtles—Leonardo, Raphael, Donatello, and Michelangelo—were no longer turtles at all.
They were human.
Panic hit immediately. Donatello scrambled for answers. Michelangelo screamed at his reflection. Raphael broke a pipe. Leonardo tried to stay calm… barely.
When Splinter arrived and saw his sons—tall, gangly, confused humans—he froze. Then he did something unexpected: he asked Donnie to try the same process on him.
And it worked.
For the first time in over a decade, Master Splinter stood as Hamato Yoshi once more. Older, wiser, still graceful, and now able to walk among the world once more. It was decided: while Donatello worked to replicate or reverse the effect, they would adapt. Splinter, now fully human again, enrolled the boys in Roosevelt High School, hoping they would learn how to exist in this strange new world.
The boys—now 17, but with no formal education or social training—were thrust into the chaos of high school life.
Day One.
The morning sun beat down on the steps of Roosevelt High. Four teenage boys stood at the entrance, blending into the crowd—but they felt anything but ordinary.
Michelangelo stood at the front, bright-eyed and bouncing, clutching his backpack like a security blanket.
Leonardo stood tall beside him, maintaining a protective presence near both Mikey and Donatello.
Raphael kept a few steps away, arms crossed, already scowling at the building like it had personally offended him.
Donatello looked pale, flushed, and tired—his body still adjusting to the transformation. His mind spun with calculations, but also… nausea.
Leo (sighing deeply): "Okay. Now that we know what we’re doing—or at least think we do—we can get through the rest of our time like this. Just… blend in. Stay alert. Act normal."
Mikey (pouting dramatically): "I hope this isn’t like yesterday again. The lockers tried to eat my arm, man. I'm telling you, they’re alive."
Raph (rolling his eyes): "That’s ‘cause you shoved your arm in like an idiot. What’d you think was gonna happen? Maybe next time, try not being dumb."
Mikey (inflating his cheeks): "Am not!"
Donnie (mumbling from behind them, wiping sweat off his brow): "Can we please just get moving…? I think standing here’s making me dizzy."
RRRRRIIIIIIINNNNNGGGG!!
The first bell of Roosevelt High shrieked through the air, and the courtyard exploded into motion. Students rushed around the four boys, heading to classes, calling out to friends, shoving books in lockers.
It was then the brothers realized… they had no idea where any of their classes even were.