A/N: Hey guys! This idea just sorta popped into my head and I had to write it out. One shot, possible two shot.

Setting: September, Marauders' sixth year.

Remus said in the Deathly Hallows that Snape 'always was a fan of Sectumsempra' but how did he know that? What if Lily gave Snape a second chance after the mishap in fifth year and he totally blew it? Implied JP/LE, depending on your point of view.

Unfortunately, I did not get the rights to Harry Potter for Christmas like I asked, so I still do not own.

Remus sighed as the train finally pulled into the Hogsmead station. He didn't mind long train rides; what he did mind was the fact that Sirius had decided to be as annoying as possible for the whole trip.

"Please stop poking me."

"But it's fun!" Sirius whined, prodding him in the side. Remus turned to him.

"Fun for you, maybe. Now can you move? I have to go hold open the train doors."

Sirius sighed dramatically and moved out of the way. James heard and looked up from his game of Exploding Snap with Peter, smirking, "We warned you about all the hardships of being a prefect when you got that badge, Moony."

Remus rolled his eyes and left the compartment, muttering about his choice in friends.

"Come on," said James as Remus disappeared in a crowd of students outside their compartment, "We need to hurry if we want to get a carriage to ourselves."

The three remaining Marauders changed quickly and left the train in the throng of students. Somewhere farther along, they could hear Hagrid calling for the first years.

"Hurry up, Pete," said Sirius in annoyance as Peter tripped and stumbled, falling behind a little, "I want to get a compartment to ourselves, hopefully as far away from Snivellus as possible-"

"Why? So you can spend the rest of the year seeking him out to pick on him?"

Sirius, Peter, and James turned around. Lily Evens stood behind them, arms crossed, red hair flying slightly in the breeze, the expression on her face tight and suspicious.

"Hey there, Evans," said James with a mischievous smile, "Couldn't stay away from me, huh?"

Lily's green eyes narrowed dangerously, "Unfortunately it does seem like I'm unable to, considering we go to the same school and Remus likes to hang out with you. His reason why still eludes me."

"Ah, so you only follow us around because of Remus, do you Evans?" said Sirius slyly, elbowing James in the side, "You've got some competition, mate."

Lily flushed, "First off, I do not 'follow you around', I am just unlucky enough to be forced to coexist with you. Secondly, I do not fancy Remus if that's what you're implying-"

"So you admit you fancy me!" said James with an air of reveling the solution to a great mystery.

"I do not fancy you, you arrogant twit!" Lily hurled the words at James, face flushed with rage.

"Lily?" a voice came from behind the girl and Severus Snape came through the crowd. He tugged gently on her sleeve, "Come on, I found us a carriage-"

"Oh, sending Snivilly to do your dirty work, Evans?" Sirius taunted in a baby voice, "It's obvious who wears the pants in the relationship."

James looked at him weirdly, "What are you on about?"

"It's a Muggle expression."

"So how would you know it?" asked Remus as he stepped through the crowd behind the boys.

"I take Muggle Studies!"

"And you actually pay attention?" said James in disbelief, "Mate, we've got a reputation to uphold!"

"I know," said Sirius with a sheepish grin, "But how else am I going to learn things I can use to bug my parents?"

"Fair point."

Snape's face had tightened at the sight of the Marauders and his wand was already out of his pocket when Lily grabbed his wrist, "No, Sev-"

"Want to fight us, Snivellus?" Sirius sneered, withdrawing his own wand, "Or are you gonna hide behind Evans's skirt like last year?"

"Sirius." said Remus warningly, gripping his friend's shoulder, but Sirius threw him off. Remus looked beseechingly at James, who frowned slightly and addressed his best friend.

"Sirius, come on, Remus is right, let's just get a carriage."

"What's the matter, Potter?" Snape spat, "Gone soft over the summer? Or are you just scared to fight me?"

James ignored him and gently tugged Sirius's arm, "Come on, or the carriages will all be full."

Sirius continued to glare at Snape, then slowly lowered his wand. He glanced at his friends, then pocketed it. The Marauders turned as one and headed to the rapidly shortening line of carriages that would take them up to the school.

Lily frowned after James in slight confusion. Why had he ordered his friend to stop? All it had taken was a look from Remus and he immediately told Sirius to back down?

Snape was furious. He wanted to fight! He wanted to show Lily that he was better than those arrogant fools! He raised his wand and took aim between Sirius's shoulders.

"Sev, NO!" Lily shouted. James heard her and turned as Snape cried a spell he had never heard before, "Sectumsempra!"

James plowed his shoulder into Sirius's, successfully knocking his friend out of the way, but at the same time, placing himself into the line of fire.

"James!" Remus yelled as his friend was blasted past him, landing some ten feet away with a cry of pain. Remus, Sirius and Peter rushed to their friend as Lily turned on Snape, furious.

"They were leaving! They pocketed their wands and walked away! Why couldn't you have left it at that?!"

Snape's eyes were wide as he stuttered, trying to find some excuse, "I - they - after everything they've done, can you blame me?"

Lily's face was scarlet with rage, "I defended you because they started it and you were only trying to defend yourself! But they were walking away - do you understand me? - they were walking away from a fight for once, but then you-"

But she was interrupted by a cry of pain. Whirling around, she realized that in her fury she had forgotten the victim of the attack - for it truly was an attack, she had to admit, not self-defense. A circle of students had clustered around the Marauders, three of whom seemed to be panicking, one lying frighteningly still on the ground.

"Sev," she said, quiet and serious, "What spell did you use?"

Snape said nothing. He still seemed in shock as to what he had done.

"Severus, what did you do?" Lily said insistently.

Suddenly, Snape's face hardened and he said in a cold voice that sent shivers down Lily's spine, "Nothing that he didn't deserve."

Sirius looked up and Lily felt fear clutch at her heart as she took in the naked fear on Sirius's face, visible even from this distance. His voice was desperate and full of terror, "Someone get Madam Pomfrey!"

And as several students took off in a sprint towards the castle, Lily managed to glimpse a horrible scarlet color covering the figure on the ground. She looked at Snape, horrified.

He turned and looked at her and for the first time, she understood why James and Sirius and Mary and so many others kept warning her about him. There was no remorse in his eyes. There was no guilt for mortally wounding another student. For the first time, she could easily picture him, face blank, black eyes cold, firing the Dark Mark into the sky.

"Lily…" he reached toward her, but she recoiled, gazing at him in mounting fear, of what he had done and what he had become.

"You've gone too far this time, Severus," she whispered and, ignoring his calls of her name, she turned and sprinted towards the still form of James Potter.

Several students surrounding the fallen Marauder were crying. Older students were trying to push terrified second years to the carriages. Hagrid had already departed across the lake with the first years. Boys were pale and shocked. Girls were clutching each other in horror, unable to look away from the scene.

Peter was sobbing hysterically into Remus's shoulder, unwilling to look at the boy who, not twenty minutes ago, he had been playing Exploding Snap with. Remus was pale grey, staring at his friend. The metallic sting of blood invaded his sensitive nostrils as he patted Peter numbly on the back. He knew enough from spending so much time around Madam Pomfrey to know that loosing that much blood was dangerous. He could feel the wolf stirring inside him at the scent of its pack mate's blood. It snarled in anger, demanding revenge. But Remus pushed Moony down. Revenge could wait until James was safe.

Sirius was too lost in fear to even think about revenge. His shaking hands, slick with James's blood, were pressed firmly on his best friend's chest in an effort to stem the flow. What the hell was taken those students so long? James was deathly pale, glasses lopsided, eyes closed and mouth gaping. Only his shuddering breaths and faint moans reassured Sirius that he was still alive. As he sat there in the dirt, trying to ignore the shocking scarlet covering his hands (there was far too much of it. Should there be this much?) the only thought that could break through his panic was: this is my fault.

Lily fell to her knees on the ground between Sirius and Remus, staring at the horrible sight before her. This wasn't how it was supposed to be. James was supposed to be grinning and teasing, doing his best to either woo her or escape her wrath due to some childish prank. He was meant to be the fun-loving, Quidditch-obsessed nuisance. Not this pale form drenched in scarlet, looking dangerously close to the edge of death.

Wanting to help, but unsure of what to do, Lily placed a shaking hand on Sirius's shoulder in what she hoped was a comforting way. He seemed to barely notice her as he continued to try and steam the flow. Face pale white, he muttered an interesting string of both curses and prayers under his breath, eyes locked on his friend's face.

How long the four sat by the fallen boy, none of them knew. But then, almost suddenly, Madam Pomfrey was rushing up to them, followed by a chalk white McGonagall. It took some convincing to pry Sirius off of his friend, but soon James was levitated onto a stretcher and whisked away to the hospital wing, followed by the three Marauders and the Transfiguration professor. The shaken students dispersed, making their way to the carriages. The only evidence left behind of the incident was a shell-shocked red head and a large patch of blood soaked dirt.

Wow, I'm a horrible person. What with this and what I'm planning for in later chapters of Trip Through Time. But no spoilers! ;)

I can't decide if I should write another chapter or not. Leave a review with your opinion and I'll tally the votes.