Disclaimer: I own nothing, and am writing this story simply for my own enjoyment (and hopefully yours). This is my first Harry Potter story and it involves an OC, a first for me as well.

Chapter One: THE PROPOSAL

Olivia Potter, twin sister of James Potter, was enjoying her last ever Hogsmeade weekend with her boyfriend of only two months, Remus Lupin. Olivia looked like her brother, with the same hazel eyes and black hair. But while James' hair was wild and untamable, hers had a beautiful wave to it, reaching just below her shoulders. She was a very attractive young woman, although she didn't realize it, which only added to her appeal. Any guy that looked at her the wrong way faced the wrath of James Potter. James was extremely protective of her, as she was his "baby sister", when in reality she was only 20 minutes younger than him. Olivia and Remus were in the Three Broomsticks, discussing their NEWTs and their plans after next weekend's graduation when Rabastan Lestrange suddenly appeared next to their table.

"Olivia Potter, will you do me the honor of being my wife?" he asked in a haughty tone, as if he couldn't imagine her declining.

Remus stood immediately, wand out, and Olivia was unable to formulate a response. Had Rabastan Lestrange just asked her to marry him? What was going on? Before she could answer, however, her brother's best friend, Sirius Black, banged the door to the pub open.

"Livy!" He called over the chatters of the Hogwarts students relaxing after exams. He spotted her, but then saw Rabastan standing over her, and his grey eyes narrowed slightly. He strode purposefully over, and grabbed Olivia's hand.

"Sirius, what is going on?" Olivia asked him, her hazel eyes meeting his slate grey ones, ones that she was surprised to see held fear and worry.

"Marry me, Olivia," he said gravely, trying to impress upon her the severity of the situation. Olivia looked to Remus, who looked ready to kill Sirius. She returned her gaze to Sirius' whose eyes were pleading with her to understand.

"But, Sirius…" she began, but was cut off by him shaking his head violently.

"Just say you will, Liv, and I'll explain everything." He glanced at Remus whose grip was tightening on his wand. "To both of you."

Olivia was confused at Sirius' odd behavior, and worried that he might have been Imperioused. "What color are my bedroom walls?"

Sirius smiled slightly, and then responded, "lavender. With mint green carpet."

Olivia nodded, convinced that this really was Sirius and that there must be some sort of explanation for his bizarre request. "Yes, Sirius, I'll marry you," she said, ignoring the look of hurt in Remus' eyes. "Now what the hell is going on?"

Rabastan glared at Sirius, then shoved him as he walked away, muttering, "you can have the Potter whore, Black." Sirius had his wand at the shorter man's throat, and growled, "don't you dare talk to her that way. Get out of here. And tell all your little Death Eater friends that Olivia Potter is spoken for." His grey eyes flashed dangerously, and Rabastan cowered a little at the intensity there, then nodded and left the pub silently.

Sirius saw that they had attracted a crowd, and so he threw a few galleons on the table and motioned for Remus and Olivia to follow him out.

Sirius turned to Olivia. "Livy, I'm sorry," he began, but she cut him off.

"What the hell was that?" she asked, her hands on her hips as she looked up to her brother's much taller friend. Olivia was only 5'2", and Sirius was easily 6'3". Her hazel eyes were full of fire, and Sirius realized that she really was beautiful, he had just tried to deny it for the last seven years.

He sighed, and raked a hand through his hair. "The Ministry passed a law five minutes ago requiring any pureblooded witch of age to accept the proposal of one of the first three pureblooded wizards to ask for her hand in marriage." Olivia gasped, and took a step back from Sirius. He reached for her hand, and held it while saying "I received a letter with a list of eligible pureblooded witches not already engaged to another pureblood wizard. Your name was at the top of that list, Livy." He turned to Remus for the first time, sadness in his eyes, begging for understanding from his werewolf friend. "Remus, I had to. I'm sorry, I never meant to do this to you, I just knew I had to protect her."

Remus nodded slowly. "Sirius, I forgive you. I know this is hard for you, but I also know I would much rather see her marry you that Rabastan Lestrange."

Before Sirius could respond, however, a fist came and hit Sirius squarely in the face. Sirius staggered back and James Potter stood before him, preparing to hit him again. Olivia stepped between them.

"Livy," James growled. "Stand back."

"No, James. Sirius just saved me."

He looked down at his sister. "This bastard just asked you to marry him and you accepted!" he shouted. "How the hell do you call that saving you?"

"James," Sirius began.

James whirled on his best friend. "No, I don't want to hear anything from you. What the fuck are you doing with my baby sister?" he yelled.

Olivia stood in front of her brother, her stance defiant. "Just before Sirius asked me to marry him, Rabastan Lestrange asked me." She saw her brother's face pale.

Sirius began again. "James, the Ministry just passed a new law that requires all pureblooded witches to accept one of the first three proposals from a pureblood wizard. Prongs, they sent me a list. A fucking list. And your sister's name was at the top." James took a step back, his eyes widening. "You grew up in a pureblood family where your parents loved you and each other." Sirius looked down at the ground and cleared his throat before raising his eyes to meet James', a new determination in them. "Did you know my father rapes my mother on a regular basis, James? Did you know he beats her and us? Merlin, Prongs, I couldn't let that happen to Liv. As an eight-year-old boy I watched as my father raped my mum, to build character, supposedly. James, please, I need you to understand. I have to protect her."

He turned to Olivia, who now had tears in her eyes. "Please, Liv, please understand. I," he paused and took a deep breath. "I couldn't let you marry someone like my father." He took in a shuddering breath, and Olivia walked towards him and hugged him tightly, smiling slightly when he pulled her close to him. Of course Olivia had known Sirius had had a rough home life, but she never knew what it meant to grow up as a Black. And she now felt overwhelming gratitude towards him for saving her from that fate.

"Thank you Sirius," she whispered into his shirt. She raised her eyes to meet his. "You don't know how much this means to me. Thank you." He simply nodded, and held her, wanting the comfort that her embrace brought, and trying to push down the memories of that frightened eight-year-old boy. He caught James' eye over Olivia's head.

"Prongs…" he began, but James cut him off.

"Padfoot, I don't know how to thank you," he said slowly.

Sirius shook his head. "Don't you dare even try. After all your family has done for me, this is the least I can do." He released Olivia, and he took a step closer to the man he considered his brother. "James, I can finally use my name to do something positive. Let me." James nodded, and the two men hugged briefly.

Sirius turned to Olivia, who was still wiping her eyes. "Damn it Livy, don't get all sappy on me. Now, you and Remus have a nice little chat while I go send an owl off to the ministry. And stop and buy you a ring." He held up his hand when Olivia tried to protest. "I am taking this marriage seriously, Liv. Don't you even think for a second I won't." With that, he turned and headed back into the heart of Hogsmeade. James gave a last look at the couple standing there, and then followed his friend back into the village.

I hope you enjoyed the first chapter. I really appreciate reviews!