They carried him through the woods on a stretcher, as she straddled his chest and covered his eye with two glowing hands. She was so absorbed in her task that she barely spoke, except occasionally to criticise the stretcher-bearers' unsteadiness over the rough terrain. The circumstances weren't ideal for such a complicated procedure as the one she was currently performing, but as they were still several miles from Konoha they had been forced to make do. The eye was one of the few left of its kind, and it was in danger.

"Can't you just take it out of him?" one young ninja had asked. "No sharingan is worth the pain he's going through."

The pink-haired medic hadn't even looked up. "If I thought he could live without this eye, it would already be gone. But I'm sure that even if I removed the damn thing to save his life, Hatake Kakashi would never forgive me. So instead I have to just sit here and be brilliant as I try to stop it from killing him." A drop of sweat rolled down the tip of her nose and fell onto Hatake Kakashi's chest, leaving a dark spot on his shirt.

Haruno Sakura was tired and uncomfortable and out of her depth, but as she probed deeper into the nerves and vessels surrounding her ex-sensei's eye, she knew she had to be more controlled than ever. There was already so much chakra flowing in and around the sharingan that adding her own could easily do more harm than good if she wasn't careful.

The semi-conscious jounin's body suddenly convulsed with pain, almost toppling Sakura off her precarious perch. She swore under her breath, trying to recover the loose threads of chakra trailing from her patient. Only one chance, she thought to herself for the hundredth time. Only one chance to save them both. Feeling around with her chakra, she was able to get a clearer picture of the curious eye. A normal eye needed very little chakra, and as such most people only had one chakra vessel per eye. But those ninja with an optical bloodline limit such as Uchihas and Hyuugas had a secondary chakra vessel that ran along the optic nerve. This helped to regulate the flow and prevent overloading.

Sakura had read about the dōjutsu kekkei genkai from a fifty year-old medical journal. In the same chapter was a handwritten footnote, just a few sentences outlining a newer case in which a sharingan eye had been successfully transplanted into a person outside the bloodline; and hence lacking the extra chakra vessel. Basically, it was like having opposite lanes of traffic on a one-way street. There was a greater strain on the existing outlet, leaving the eye constantly activated and at greater risk of injury due to overuse. She recognised Tsunade's handwriting and Kakashi's unique circumstances, and had burned the information into her memory just in case.

Unfortunately, the time had come for her to use what she had learned. Her chakra had reached the overexerted vessel, and she could feel how much trauma it had experienced as a result of the recent battle. Kakashi's chakra was flooding to the eye, and very little could flow back out against the current. The resulting pressure was the cause of his agony, and if it continued to build then the sudden release of so much raw energy could prove fatal. Carefully, she sent out the tiniest amount of her own chakra into the vessel, moving against the current. If she gradually redirected the flow, she could safely drain the excess chakra from the sharingan without damaging the entire circulatory system. Blessing the gods for her natural control, she pushed a little harder.

Then something happened. Perhaps someone carrying the stretcher had stumbled, or perhaps Kakashi had shifted slightly beneath her. Whatever the reason, Sakura's focus slipped. It was only the briefest of moments, but it was enough for her thread of chakra to weaken. Instead of pushing back Kakashi's chakra, it got caught up in the flow and flushed back into the sharingan. Trying not to panic, the medic strengthened her tie on the thread and dragged it back out along the vessel.

Almost at once she felt the difference. Just as the copy nin's chakra felt different immediately after being filtered through the sharingan, so too did hers. It was like it had been dipped in the pool of trapped memories inside the eye, soaking up their essence. There were no concrete images or remembered hand seals, just an overwhelming feeling of horror and a dizzying tincture of bloodlust. She cried out in shock and nearly severed Kakashi's optic nerve with her chakra scalpel. Ignoring the others' concerned questions, she examined the little she could see of Kakashi's face. He did not appear to have been affected. If anything, his condition seemed slightly improved. His breathing was no longer ragged and his heartbeat was slowing back down to its normal pace.

She smoothed the hair back from his clammy forehead and tried to muster the courage to examine his eye once more. Konoha couldn't be much further away. Once they arrived, there would be Tsunade and a whole team of medics more experienced than she to help him. If he could hold on for a little while longer, she wouldn't have to risk feeling like that again. But even as the thought to do nothing entered her mind she dismissed it. If she didn't make sure Kakashi was really okay and something happened to him later, she would never forgive herself. Closing her eyes and mustering her last reserves, she swept her chakra over his sharingan, entering the vessel further down from the opening. The current seemed to be stabilising, moving away from the eye. Withdrawing her own chakra must have been enough to reverse the flow of his.

"Um, miss Haruno?" the same young ninja began tentatively. "Your nose is bleeding."

He watched the medic draw her gloved hand impatiently across her face before collapsing gently forward. For a brief moment he assumed she had fainted at the sight of her own blood, but a quick examination from one of the stretcher-bearers revealed that exhaustion was the culprit. After five hours of treating wounded ninja and one particularly tricky sharingan, she was finally free to rest. The copy nin did not seem to be in any immediate danger or discomfort, so they saw no point in waking or moving her. She didn't make much difference to the load they carried; and even if she did, it was thanks to her that most of them were able to walk at all. The young ninja thought the woman would look more peaceful in sleep than she did in the field. But when he snuck a furtive look through the rosy strands of hair covering her face, she seemed more troubled than ever.