A/N: I own nothing, it all belongs to the fabulous JK Rowling.

A Solitary Tear

The evening sun was reflecting over the Black Lake as Severus Snape walked around it. He was feeling rather pleased with himself as he had ensured that Potter had missed the Quidditch Cup final – unfortunately Gryffindor had won anyway but Snape wasn't dwelling on that – and had spent the morning watching the boy copy out detention cards belonging to his arrogant father and his friends. Snape knew that Potter had hated every minute of the detention which had pleased Snape most greatly. But in any case the boy deserved it – he had almost caused the death of another student, not to mention with a curse belonging to Snape himself!

That had infuriated Snape beyond words, knowing that Potter had his old Potions book. And the boy had the nerve to try to tell him that Roonil Wazlib was his nickname! Snape had been teaching for seventeen years, he knew a spell-check quill gone wrong when he saw one. It was clear it was Weasley's potions book. Snape was also angry with himself for leaving the old book in the store cupboard.

Although he had suspected Potter had his book since Slughorn had boasted about his talent at the Christmas Party. Snape knew the boy hadn't inherited Lily's exceptional talent at making Potions at all – in fact the only thing he had inherited from his mother was her eyes. The rest of him was more or less a carbon copy of his father – from his rude and selfish attitude to his ridiculously messy hair. But yet Snape still felt obliged to protect the boy who Lily had died for, after all it was the least he could do after what he had done to her.

He stopped and looked out across the lake, his thoughts drifting to Lily. He could see the beech tree under which he had lost her friendship forever because of one stupid mistake on his part. What he wouldn't do to back to that day and change what he had done.

As he continued to stare at the tree he noticed some movement at the foot of it – two people were sitting there, one in scarlet and gold Quidditch robes and the other in Hogwarts uniform. They were locked in a passionate embrace.

Bloody hormonal teenagers thought Snape as he started to walk back around the lake in their direction well at least I can take some points off Gryffindor for inappropriate behaviour.

As he grew nearer however he froze, staring in horror at the couple. It was like a horrible déjà vu. The boy had messy black hair and had his hands tangled through the girl's long red hair.

Flashback

It was the day of the Gryffindor verses Hufflepuff match in Snape's seventh year and it was exceptionally mild for a February morning. Snape cared very little for Quidditch, especially when James Potter and Sirius Black were playing so he had decided to take residence in the library for a few hours.

After eating a quick breakfast, Snape was heading across the Entrance Hall on his way to the library when he caught sight of Lily standing with a couple of friends by the front doors, it looked as though they were waiting for someone. Snape slowed down to see what happened. Just as he stopped beside a statue of some medieval wizard, his worst nightmare came out of the Great Hall – better known as the Marauders. Black had a girl hanging off his arm as usual, Lupin was reading an article on the front of the Prophet and Pettigrew was watching Potter as if he was some sort of god. Snape snorted knowing Potter loved the attention. It was at this point when Lily walked over to them, Snape stared in horror at the exchange that took place.

"Hey James, good luck for the match today," Lily said going uncharacteristically red.

Potter ran a hand through his hair and smiled "Thanks, Lily. Are you coming down to watch?"

Lily nodded with a smile on her face "I already told you I was last night when we were doing patrols, don't tell me you forgot."

"Just checking," Potter replied with a chuckle. And to Snape's disgust Lily allowed Potter to put an arm over her shoulder and walk down to the pitch.

Snape had proceeded to spend the next few hours in the library trying not to dwell on what he had witnessed and trying and failing to complete an essay for Herbology. Around noon he heard Lupin and Pettigrew talking on the other side of a book shelf.

"Hufflepuff don't stand a chance now do they, we beat them by over 200 points, Gryffindor are sure to win the cup again," Pettigrew was saying.

"Yes, Wormtail, I know, you've told me about fifty times," Lupin said tiredly.

"And I still can't believe what Lily did," Pettigrew went on. Snape's head snapped up; what had she done?

Lupin chuckled "I didn't know she had it in her."

"James was pleased though," Pettigrew went on.

"Well of course he was, he's only gone on about her for what – almost seven years. Now can you please let me get on with this essay, its due Monday," Lupin said.

"Okay, see you later Moony," Pettigrew replied.

Snape was now quite uneasy about what they had said about Lily ad when dinner time came around he finally left the library. However instead of heading for the Great Hall, he got a sandwich from the kitchens and went for a walk on the grounds.

He was about to step outside when he heard the horribly familiar voice of Sirius Black.

"Why hello, Snivelly," Black called out.

Snape ignored him; he wasn't in the mood for a fight and he knew fine rightly Black wouldn't take him on in a one on one duel.

"Have you heard the amazing news Snivelly or have you been too busy ordering more grease to wash your hair with," Black smirked causing a few sixth year girls nearby to giggle.

Snape turned to face him "Whatever it is, I highly doubt it will interest anyone with a higher intellect than you," he sneered.

"Oh I think this is pretty interesting. You see after my dear friend James scored about seventeen goals today – we're sure to win the cup by the way – Lily Evans finally realised that he's not a bad looking bloke – nothing on me of course – and decided to jump on him the moment he entered the common room and give him a good ole snog," grinned Black.

Snape froze; was this what Lupin and Pettigrew were talking about … but no, there was no way it could be true. "Hilarious joke, Black aren't we all laughing our heads off. But you know as well as I do that Lily would never touch that big-headed idiot, she loathes him."

"Ah Snivelly, please catch up, James and Lily – Evans to you – have been getting on fantastically since they were made Head Boy and Girl. Not to mention James has wised up a bit, pity really but I can't have everything," Black rolled his eyes. "And personally I don't think you eat the face off people you loathe."

"I don't have time to stand around and listen to your garbage, Black," Snape snapped and marched out the front doors.

"Fine, find out the hard way," Black called after him before going over to flirt with the girls who had observed the incident.

Snape was halfway around the lake when he stopped to contemplate Black's words. No he told himself Lily hates Potter, she would never go out with him. But then he remembered how often he saw them together these days. He lost himself in thought as he stared across the lake.

As he realised he was directly opposite the beech tree, he cursed himself profoundly as he thought of the fateful day almost two years ago when he had lost his only real friend in the world. As he stared at it, he noticed two people sitting there.

As he took in the scene his blood ran cold, he felt as though he couldn't breath. Even from a distance he could make out Potter, still in his Quidditch robes leaning up against the tree with a red haired girl in her school uniform sitting in his lap kissing him with her hands caught in Potter's hair. Snape would recognise the girl anywhere - Lily Evans.

Snape wanted to shut his eyes, he wanted to scream, he wanted to run as far away as he could but his feet remained firmly fixed to the ground and his eyes wide open in horror. He wasn't how long he stood there for but it wasn't until Lily pushed Potter back onto the grass and she leant over him, their lips still tightly locked together that Snape managed to turn away.

He walked slowly back towards the castle wondering if he would ever be able to erase the scene from his memory. He felt like he was surrounded by Dementors as he stumbled down the dungeon corridor to the Slytherin common room.

End Flashback

As Snape observed the scene he identified the two as Potter and the Weasley girl. He glared at them. For years he had buried that memory and because of them it had been brought back to the forefront of his mind as clear as the day it happened.

Instead of approaching them and taking every point Gryffindor had off them like he so wanted too, he turned on his heal and returned to the castle cursing Potter and his girlfriend.

He decided the best way to punish them would be to keep Potter in detention for as long as possible. That way he would have less time to spend with Weasley who would be spending a lot of time studying for her OWLs anyway.

But even though he tried to rebury the memory it haunted him the whole way back to his office but for a different reason than it had before. All those years ago he had felt he had lost everything because Potter had got the girl he loved. But now he truly knew how it felt to lose everything. And now he wouldn't even care if Lily was with Potter, if only she was alive and happy.

Snape knew he had only himself to blame for her death and as he ascended the marble staircase to his office, a solitary tear rolled down his cheek.

-The End-

A/N: Hope you enjoyed :)

This is just something that came to me when I was reading Half-Blood Prince and Harry thinks Snape is keeping in detention for longer on purpose.