Author's Note: This chapter was harder for me to write, but I did it! Anyways, I know the heart transplant procedures aren't entirely realistic, but it's fiction ;) I can do whatever I want with it. Also, please review :)

Disclaimer: I do not own the TMNT.

Raphael sprinted through the sewers, panting heavily. Pain tore through his entire body with every step, every move of his arms. His lungs were burning and his sides were on fire. Raph's right arm was wrapped around a silver case with harsh red lettering. He held the case tightly to his chest. His feet splashed with the sewer water. He drove onwards, ignoring his pain. He grunted and winced as his left calf shot up in agony.

"You have five minutes…"

Raph shook it off. "Mind over matter…" He muttered under his breath as he ran.

~.~.~.~.~

Don shakily donned rubber gloves and proceeded to his operating area. Mikey lay with his eyes closed atop a lab table. Multiple tubes were connected to the unconscious turtle's neck. His skin was deathly pale. Don took a deep breath. He walked over to Leo's unconscious form, a mere two feet from Michelangelo and performed a final check-up. He nodded once he was satisfied with the results and kept two makeshift heart lung bypass machines at the ready.

Don began the operation with an incision down Leo's plastron, splitting the elder turtle's breastbone. "No time for screw-ups now…" Don thought to himself.

~.~.~.~.~

Raph staggered into the lair, breathing heavily. He leaned against the wall. He groaned and kept moving, leaning on the wall for support. He made his way around the wreckage of the lair. Raphael huffed and stepped into Don's lab. Donatello stood waiting by Leo's side. The elder turtle was a gruesome image, his plastron had been cut open and there was an almost empty space where his heart had been. The only thing keeping the elder turtle alive was the hissing machine behind him. A tube of some sort was hovering over Leo's open chest, it huffed a cold gas over the open area. Don's gloved hands were covered in blood.

"Hurry up; we don't have a lot of time! Give the heart to me." Don hissed. His eyes were wild with anxiety. Raph nodded and set the case on a table. He quickly opened it, revealing the small metallic construct. It hummed faintly and seemed to emit a pale glow.

Raph donned gloves quickly and removed the heart from the casing; it was cold to the touch. He handed it to Donatello who quickly snatched it and ran to Leo's side. He began a series of quick movements, removing and adding tubes from Leo's body. He gently and carefully lowered the artificial heart into Leo's chest cavity.

Raphael stared and put his hand to his mouth quickly as he watched Don move flesh around the heart. Raph had seen a lot of gory battle-wounds but he was unprepared for this sight. He took a few steps back. Don's eyes snapped up. "Don't you dare leave me right now." Don snapped, he turned back to his work. Raph looked sick; he turned his head away from the procedure and focused on not hearing the sickening sounds of the surgery.

Don gasped. Raphael turned about and his eyes went wide. The artificial heart extended tubes from inside of itself to connect with arteries and the remains of the old heart. It emitted a small vibration. Don stepped back, though watching the entire surprise with a nervous shudder. The heart froze in place and the screen monitoring Leo's vitals began beeping. Don stared in horror. Raph had no inkling of what was going on. He turned from Don's horror-stricken posture to the beeping monitor. His adrenaline began to rise with fear.

"Don, what's happening?" Raph shouted above the beeping.

"The heart-it-it's being rejected by his body!" Don cried, shaking his head with tears streaming down his cheeks. Raph froze in place. He felt a chill run through his body. Raph clenched his fists as tears slowly streamed down his cheeks. "After everything… he's just going to die…" Raph thought to himself. He closed his eyes.

"Don, do somethin'!" Raph yelled angrily, his eyes snapping open.

Don looked to his second eldest brother with red eyes. "I can't, this is beyond my control." Leo's body suddenly jerked. The two brothers stared at Leo in shock. The artificial heart in his chest slowly began pumping. It hummed faintly before pumping at a steady and healthy rate. Don shook his head. "It adjusted to suit his body…" He whispered in awe. Don shook his head to clear his thoughts. "Raph, can you go outside, I can handle the situation now."

Raphael nodded numbly, hardly believing what had just happened. Don turned to Leo's body and began closing up his chest. Raphael walked outside of the lab and closed the door. He sat down on the floor. Raph closed his eyes and took a deep breath. "He'll be okay…" He whispered with a smile.

~.~.~.~.~

Don walked out of the lab with a small smile. He noticed that Raph had dozed off next to the lab door. The red masked turtle was snoring and sitting with his shell to the wall whilst his mouth was wide open. Don chuckled at the sight. The purple masked turtle turned his eyes to the wreckage of the lair and suddenly stiffened. His smile disappeared and was replaced with a snarl.

A small group of Foot ninjas clothed in dappled gray stood amidst the wreckage. Don glared at them as he reached into his belt for his shuriken. The ninjas stood still, they watched Donatello intently. The tallest of the group stepped forward with open hands. "We mean no harm to you or your family. We are simply here to help guard your wounded brother and Master Leonardo." The ninja spoke with a smooth and calm voice. Don noticed that he had blood on his right leg along with a shallow tear.

"You have the nerve to come here and try to trick me after what you've done to my family? Forget it." Don snapped. The leader of the group lowered his hands. "Not everything is as it seems, Donatello-san." The ninja said. "We will not take violent action against you." Don's eyes narrowed.

Donatello brought his arm back to hurl the shuriken, a hand quickly grabbed his wrist. Don looked up to see Raph holding his wrist. "Raph, they're the enemy! They hurt our brothers!" Don cried in surprise. Raphael shook his head. "These guys aren't the enemy, bro." Raph turned and nodded in the lead ninja's direction. "That guy right there saved my ass and Leo's life. He brought me t'the heart and he gave me a way outta the Foot Tower." Raph turned back to Don with a small smile. Don stood tense for a few seconds but sighed and stood straight. "Okay, if these guys did as you say, then they can stay. But at the first sign of trouble, I won't hesitate to strike." Don said.

Raph grinned and gave his younger brother a noogie. Don protested at first but found himself chuckling as he tried to escape Raph's hold.

Tenjin smiled softly underneath his mask at the sight and turned to his comrades. Eleven ninjas stood waiting for his command; one had twin teak nun chucks in his belt. "Alright, let's set up a perimeter. No enemies get in, and we make damn sure that Master Leonardo and his family are safe."

"Hai," the ninjas chorused.