I have finally been able to get rid of laziness, so this story is only mine. :D

This story takes place after the guys finally defeated the Triceratons, the Kraangs and the Shredder.

Master Splinter is still alive.

Summary: The death of one of the turtles threatens to drag the entire Hamato family to a tragic end. They will have to find whoever's responsible to prevent it.

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A simple equation

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"He is gone…" Doctor Rockwell told with deep sorrow and enormous frustration to Mikey's whole family and friends, after slowly turning his back on the stretcher where the corpse of the young turtle was lying. He had tried to save the prankster from the grip of such a cruel fate.

Feeling completely defeated, he dropped his hands to the sides of his simian body. His brain that had acquired the talent to read the minds of others through his mutation was filled with a wave of thoughts from everyone else, all without exception drowned in affliction, agony and torment.

After hearing those words, Master Splinter's breath became labored, he staggered until he fell to his knees, tightening his grip on his walking stick which hadn't been enough support to prevent his fall; he put a tremulous hand on his chest, scrunching his robes up he squinted his tearful eyes as he murmured his youngest son's name with a bleak tone.

Raphael began to tremble feeling such rage against life that if hadn't been for Leonardo who was as pale and trembling as his temperamental brother, he would have lost his sanity, but the leader embraced him tightly, saving not only the mental health of the tough turtle but also his own after having both to admit because of such atrocious news, that all their efforts for the young freckled turtle had been in vain.

Feeling his blood grow even colder because of those words, Leatherhead, quietly and with his gaze fixed on his little friend's body, shed many tears knowing that he would never again share another tender or funny moment with the sweet turtle who had honored him with infinite trust, saving him from pain and fear with his smiles and gentle words of encouragement.

April and Casey, barely breathing, like everyone else, after enduring long minutes filled with anguished expectation, had gone from firmly holding hands to being wrapped in a hug in which both of them couldn't yet believe what was happening. It looked like Mikey was gonna be okay, not that everything would get complicated. It was a far more horrendous reality than a nightmare.

Slash, despite having such a wild and indomitable character as his former owner, but increased tenfold by his mutation, had managed to show the respect the situation deserved because he was convinced that although he had decided to dedicate his life to finding and slaughtering the culprit, that wouldn't mitigate at all the anger and suffering of those who would live in a deep melancholy from that day forward.

But something weird was going on. After a few minutes, Rockwell felt someone was missing... He turned around again and looked with horror at the turtle he had tried to help save the young life that shouldn't have died out before time.

Donatello, completely paralyzed on the opposite side of the stretcher, had his eyes fixed at Mikey's pale face but at the same time he seemed to be staring off into space. Rockwell felt bewildered after having noticed that he couldn't read the mind of the turtle who at the same time had become an engineer, scientist, and doctor for the good of his entire family.

Perhaps his young colleague's brain had begun to degrade because of the pain of losing a loved one who wasn't only his brother but also his best friend? Or maybe Donatello would be entering into a state of insanity in which not even Rockwell's extraordinary mind-reading powers could help him? Or, perhaps... by divine action, could the young prodigy be finding the solution to death itself?

Many more questions could have been begotten in the mind of the ex-human scientist if it hadn't been because the purple masked turtle began to laugh with so loud and callous wildness that everyone else fixed their eyes on him, their eyes full of fright which almost immediately turned into deep anguish.

Before anyone had the courage to do or say anything, Donatello went from his infamous guffaw to shouts overflowed with guilt.

"IT'S MY FAULT! I KNEW IT! I KNEW IT! I'M NOT INFALLIBLE, AT SOME POINT IN LIFE I WAS GOING TO MAKE A MISTAKE! I SHOULD NEVER HAVE THOUGHT I WAS SMART ENOUGH TO SAVE HIM!" Those accusations toward himself followed by his own trembling hands squeezing the sides of his head moistened with a cold sweat as his mouth contracted in painful and grotesque grimaces of hatred against himself, encouraged him to rise his gaze to discover how the others looked at him with horror and confusion.

Everyone knew the hard work the smartest one among them had to face when one of his brothers was ill, injured or worse, near death; the results of all his efforts were entirely his responsibility. Donatello's affection for Mikey was always as remarkable as it was quiet, taking care of him just as Leonardo or Raphael did. Mikey had told him countless times that he was his favorite turtle. It was obvious that his pain at losing his baby brother was going to break his heart, but no one ever thought that pain could reach such a level of neurosis.

"I'M SORRY MIKEY, I'M SORRY! PLEASE FORGIVE ME! I AM THE ONE WHO SHOULD DIE! That last cry, an unmistakable sign of a soul that has completely detached itself from the joy of living, was the signal for someone among those present to finally react. Unfortunately, because of the confusion in everyone's heart, no one was quick enough to stop Donatello when he ran after slamming a syringe that he still had in his hand against the floor with frightening fury.

Donatello, possessed entirely by the resolution he had just made and with his eyes fixed on one point, hastened his escape to lock himself in a place of his laboratory where he had built a bomb shelter in case the Kraangs were planning to destroy that part of the city.

The ones who were quicker in trying to catch up with Donatello, only managed to hit with their bodies the heavy metal door that almost had the thickness of a bank vault door and thanks to the smartest turtle's computer had closed itself immediately upon hearing the command from its creator.

"Donnie!"

"Donatello!"

"My friend!"

"My son!"

A few seconds passed before the others' shouts could get an answer to their pleas. The muffled sound of a gunshot caused the blood in everyone who loved Donnie to freeze in just an instant.

To be continued…