A/N: I have no idea what made me think of this, but it just sort of popped into my head. Hope you enjoy it! And please review!!

The Thunder Storm

I've had enough, Severus thought viciously as he watched them from across the grounds. That arrogant git Potter had his unworthy arm around her waist as they leaned against a beech tree.

It was one of the first evenings where the weather had been descent, although dark clouds hung threateningly over the horizon. Many people, obviously including Potter and Lily, were taking a break from their studies to enjoy the nice weather.

Lily laid her head on Potter's shoulder and closed her emerald eyes. A small smile played on her beautiful face; she seemed very content. Potter took his hand from around her waist and began to run it through her dark red hair. Potter's mouth was moving, but Severus could not make out the words. Whatever he said, Lily giggled and nodded. The both stood and walked toward the castle, fingers intertwined, as the storm clouds moved closer.

Severus's body seemed to move of its own accord as he followed them back to the castle, though he was keeping a good distance behind them, while his mind formed a plan. He stopped when his pursuit had paused to give the password – "phoenix tears," he heard Potter say – before the couple entered the Head's Common Room. Once the portrait had closed, Severus slid down the wall and sat on the floor as low rumbles of thunder echoed over the grounds.

He knew that something had to be done about that idiot. Potter, who had made his life a living hell for nearly seven years. Potter, who had beat him in everything. Potter, who didn't deserve Lily.

A shiver ran through his that he knew had nothing to do with a draft in the old castle. At one point, he and Lily had been best friends; before Potter, before they had been sorted into different houses, even before Hogwarts. Even at the young age of ten years, Severus had known that there was something special about Lily, something extra in her brilliant green eyes.

No one else understood how the popular Gryffindor and the unliked Slytherin had such a close friendship, but the hadn't cared. But, as so many childhood friends do, they slowly began to drift apart. Lily started hanging out more and more with her giggling dorm mates. Severus wanted the approval of Avery and Mulciber, who had connections to the Dark Lord. And although stories of the Dark Lord had intrigued Severus very much, he started to realize how much he cared about – how much he loved Lily.

But then he had made that one, fateful mistake. He had called Lily, the girl he loved, an unforgivable word.

Mudblood.

From that day forward, she had wanted nothing more to do with him.

It was all Potter's fault, Severus thought viciously. It was only after being humiliated and tortured by Potter that Severus had been driven to let that disgusting word slip and had lost Lily forever.

A flash of lighting and a clap of thunder brought Severus back to the present. He looked at his watch; it was getting late. Surely they had gone to bed by now. But he waited a bit longer, incase the thunder had woken Potter up.

Nearly half an hour later, Severus stood and approached the portrait of a young man leaning against a tree.

"Phoenix tears," Severus said. The portrait swung open. At first, he did not enter, but simple looked inside the common room to see if anyone was there. Apparently, Potter and Lily had gone to bed. Severus went through the portrait hole as he withdrew his wand. The common room where he stood was cozy, with a squishy couch facing a fireplace. There was also a table with various books, quills, and pieces of parchment.

Severus made to advance, but something silvery caught his eye. He found the source draped over the back of the couch. He picked up the flowing material, instantly knowing what it was: an Invisibility Cloak. He doubted very much that it belonged to Lily, which meant that it had to belong to Potter. Yes, that would fit – it was no wonder that he got away with most of the stuff he and his gang did.

He threw the Invisibility Cloak over his shoulders, watch his body disappear as he did so. He grinned. There was something poetic about using Potter's cloak to assist his plan. Severus pulled the cloak over his head and moved toward the two doors that were opposite the portrait hole. He assumed that one of them was Potter's room, while the other's was Lily's. Instinctively, he moved to the one on the left.

Making sure that all of the lights were out in the common room, he cracked the door open.

He waited. There was no sound coming from the room besides that of steady breathing. Severus looked through the crack in the door. He couldn't see Potter or his bed, but he could see a Quidditch poster on the wall. This had to be Potter's room.

Quickly, he opened the door wide enough for him to slip through. It was only when he had silently closed the door id he realize that there was not one, but two figures in the bed. Once his eyes adjusted to the light that the half moon gave did he notice the smooth, creamy skin and dark red hair of the second figure.

It was Lily – his Lily – in bed with that bastard. He shook with anger and heartache under the Invisibility Cloak. Potter was laying on his back, with Lily half laying on him, half laying next to him. His hand ran lightly over the creamy skin of her lower back.

"Can I ask you something, Lil?" Potter said softly.

"Hm." was Lily's reply.

"Why do thunder storms turn you on?"

Lily laughed as she sat up slightly to look at him. "I don't know. Why does anything turn anyone on? It's just one of those things I guess. Besides, I didn't hear you complaining." she added slyly.

"Nor will you." Potter said as he leaned closer to Lily and kissed her.

Severus wanted to break something.

Lily gazed out of the window for a few moments before saying, "Can you believe that we are nearly done at Hogwarts?"

"Weird, isn't it? But just think – we have the rest of our lives to look forward to."

"Speaking of which, did you decide what you were going to do?"

"Yeah, I finished the application and I'll send it to the Auror Office on Monday."

Even through the semi–darkness of the room, Severus could see the worry on Lily's beautiful features.

"Hey now," Potter said as he pushed a strand of red hair behind her ear. He too had noticed her worried expression. "I'll be fine."

"But you don't know that." Lily said in anguish. "The Aurors are on the front lines. But I know that you would never be satisfied doing anything else."

"Then you can tell that to my mother."

"Speaking of parents, mine really want to meet you."

"I guess we can't hold it off any longer, can we?" he sighed. "Is you sister really as bad as you say she is?"

Lily laughed as Severus repressed a snort. "James, she's much worse. And she'll hate you right off the bat because, one, you're a wizard and, two, you're my boyfriend."

"Yeah, that'll be fun." Potter said sarcastically. "Hello, may name is James Potter and I'm the wizard who is sleeping with your sister."

Lily smacked his shoulder. "That's not funny," she said, though there was definitely a hint of a smile on her lips. She yawned as she laid back down on the bed. Potter wrapped an arm around her waist.

"Goodnight, love," he said softly.

"G'night," Lily murmured. Within minutes, they were both asleep.

Severus backed out of the bedroom, just as quietly as he had entered. Tossing the Invisibility Cloak back were he found it, he left the Head's Common Room.

He wasn't sure how long he roamed the castle. It could have been minutes or hours. As a single tear slid down his face, he realized he had truly lost Lily...forever.