Pairing:
At first Lily/Snape, then OOC/Snape and Lily/James (but Sev ends up alone)
Remus/Tonks(eventually) Sirius/OOC(at first Sirius is a famous ladies man :DD) Peter P./Mary Macdonald

Summary:
What happens, when Severus one day finds a weird girl playing the piano in the great hall of Hogwarts? Who is she, and how does she make the future different than it was on J.K. Rowling's books? Summary sucks, because I can't tell anything without SPOILERS.

"Love is a game two can play and both win."
-Eva Gabor

"Watch your thoughts; they become words.
Watch your words; they become actions.
Watch your actions; they become habits.
Watch your habits; they become character.
Watch your character; it becomes your destiny."
- Lao-Tze

CHAPTER 1
"Lily! Come on!" Severus Snape whispered as Lily looked out of the window, seeing nothing but darkness. "Come on or we get caught!" Lily smiled at her best friend's eagerness and ran after him, as quietly as she could. Lily Evans and Severus Snape were 15-year-olds in Hogwarts school for witchcraft and wizardry. They were running the corridors of the castle, breaking the rules. They should've been sleeping, safely in their beds, but as it was their last night before a long summer holiday, they wanted a little extreme.
"Up to the highest tower!" Severus grinned to his best friend. It didn't matter he was in Slytherin house, and Lily was Gryffindor, though usually Slytherins and Gryffindor's weren't ... Well, not the best friends, to say lightly. But Lily and Severus were truly best friends. Had been since they were 10 years old.
"Sure Sev, now let's go before someone really catches us!" Lily hurried. She was usually the perfect girl in the class, not breaking rules, always everything right, but now she wanted to let it go.
"No-one will, I promise. Lily, trust me", Severus looked deep into Lily's eyes. Lily nodded quickly, speechless as she was.

"Isn't this great?" Severus asked for the third time, pointing up at the starry sky. Lily giggled.
"Yes, yes, yes!" she said. "I love stars. I know Tuney watches them too, every night. D'you think she sees the same stars?" Severus rolled his eyes without Lily noticing. Why did she speak about her sister up there, in a magical moment, magic that wands could never create, in this kind of moment with her best friend? But Lily cared about her sister. And Severus cared about Lily. Lily didn't want to hurt Tuney, and Severus didn't want to hurt Lily. So he had to be nice.
"I bet she does. And I think she thinks of you when she does. You or someone.. else.. that she loves", Severus struggled with the last words.
"No", Lily said firmly. "She thinks of someone she loves or likes, but that's not me. She hates me now. I'm a freak, remember? 'You're both freaks, you, my sister, and that freakiest of all, Snape's boy', she screamed. She doesn't want to waste her precious time on freaks. She's fourteen, of course she now has some guy", Lily's eyes weld up with tears. "But let's not talk about it. I love stars. They give me hope. Hope that.. that I would be better witch... And make my friends proud, but not jealous."
"I already am proud of you, Lily. At this age you couldn't be any better, and you know I'm being honest", Severus said, looking at Lily's profile. Her red hair was sprawled out on the stone-floor they were laying on. She had a magic lily in her hair, toying with her name. She looked pretty.
"Sev... Thank you", Lily turned to look at her friend, smiling a little. "I really love this, but you know, I'm tired. I need to get some sleep, and I bet you should, too." In fact, Lily was exhausted. So was Severus. But he could've done anything to be up for Lily.
"Yeah, maybe we should go", Severus stood up, holding his arms out and helping Lily up too. Lily hugged him really quickly.
"Remember, Potter's a freak. We're not. He and his friends. Not us", Lily whispered in his ear before pulling away form his arms and winking slightly. "Come on, Sev!"