25th September, 1978(?)
*The flashbacks are in italics*
Sirius' POV
I couldn't believe it. I wanted to scream, but I managed to maintain a poker face when I re-entered Marlene's room in St. Mungo's with Mr and Mrs Potter. Correction; Mum and Dad.

*Flashback*
"Sirius, can we talk to you outside?" Mrs Potter asked.
"Sure, Mum," I said and followed Dad and her outside.
"Sirius, we have signed all legal documents, talked to Walburga and Orion, and we are proud to call you- " Mr Potter began.
"-Our son Sirius Potter!" Mum finished with tears in her eyes.
I gasped.
"Thank you so much, Mr and Mrs Potter!" I exclaimed tearfully.
"Mum and Dad." Mrs Pot-Mum corrected. "However, there is a slight complication. If we die, you would have to retain your prior name." I nodded.
"Now to the hot topic. Do you like someone? Specifically, a girl whose name starts with M and who has been conscious for merely hours?" Dad asked, wiggling his eyebrows.
I blushed. Mum elbowed Dad in the ribs. "Fleamont!" She scolded.
I shrugged nonchalantly. "It's quite alright, Mum. Dad's right. Everyone already figured it out."
Dad smirked. He said, "Well, come on then. Let's get you to the love of your life."
We went back to Marlene's room, two adults smirking and the third blushing.
*End of flashback*

Narrator's POV (kind of)
After a while of joking and chatting, they exchanged their goodbyes with Mrs Potter, Mr Potter and Marlene, though James giving me confused looks. We apparated back to Hogwarts and went to the Heads' Dormitory.
"Mr team manager Lupin, I demand a change of teams in the prank war," Lily said as soon as we'd settled down.
"Sure. What change?" Remus asked.
"I want to pair up with Sirius," Lily said with a mischievous glint in her brilliant green, almond-shaped eyes.
Sure, Sirius found Lily beautiful. But not romantically, not as James did. He liked her in an annoyingly big brother way. And he'd hex anyone who hurt her, even if it was one of his best friends. Heck, he had hexed Snivellus hard when he had called Lily the m-word. She was the younger sister he never had. And the idea of teaming up with her was exciting. She was the only who had succeeded in pranking the whole school without getting into trouble.

*Flashback*
It was dinner time. The Great Hall was packed. Students were sitting at their respective house tables, stuffing food into their faces. Little did everyone know that it was going to be very eventful in a matter of minutes. Lily Evans grinned inwardly. She waited peacefully, barely eating anything.
Then out of the blue, Mathew Mulciber and Andrew Avery stood up on the Slytherin table. Their robes changed to scarlet and gold wedding dresses. Their hair grew long and their chest puffed up. They put their hands on their waists, started shaking their hips and making kissy faces towards the other tables. The hall erupted in laughter. Even the staff was trying to suppress their chuckles. Then they started twirling and shaking their heads wildly. Everyone laughed even harder. After another odd assortment of dance moves, they stopped. Both of them snapped out of their reverie and ran to the doors as fast as they could. Avery tripped, displaying his underwear. People howled. Mulciber pulled Avery up by the scruff of his neck and led him outside the Great Hall. Everyone resumed eating, chatting and laughing. Professor McGonagall went over to the marauders. She cleared her throat. The marauders turned.
"Yes?" Sirius implored.
"As entertaining as that was, I'm afraid I'll have to give you detention." She stated firmly. 
"But we didn't do it!" James insisted.
"Black, Potter, Pettigrew, 8 p.m. sharp in my office tonight." She returned to the High Table.
At that moment, James caught Lily's eye. She smirked gleefully and raised her eyebrow challengingly. His breath caught in his throat. He nudged Sirius.
"Lily did it," James said, wide-eyed. Sirius stared at him.
"No way! You're talking about Lily Evans? The biggest-nerd-Lily Evans?" Sirius asked. James nodded.
The boys didn't understand why Lily Evans would prank two Slytherins. She wasn't biased, as far as they knew.
Meanwhile, Lily couldn't help feeling good. She was satisfied with the sweet revenge she had gotten from making those rotten potatoes dance and get laughed at. All in all, it was a very eventful day. Several things happened.
It was the day Lily had been called a mudblood.
It was the day the marauders got in trouble for a prank they didn't pull.
It was the day Lily Evans grinned at Sirius Black and James Potter.
It was the day James Potter realized that he had fallen in love.
*End of flashback*

A/N
Hey guys! Okayish chapter, I know. Pardon if there are any mistakes, I typed this on my phone. Also, one day left for Christmas! At least in my country. But I'd be glad if you helped me reach 2k reads till then! If not, that's perfectly fine! Merry Christmas in advance!🎅🏻🎄
By the way, the timeline was a little messed up so now I will write the dates on which the day commences.
What's your favourite thing about Christmas? Send in the comments!
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Love y'all!
-JilyLover18❤️❤️❤️