Peter first found out about his half-sister from Storm.
It was soon after the school was rebuilt and after Erik Lehnsherr had left, and Peter and the newly-minted X-Men were hanging out in the garden after yet another grueling session with Mystique and Beast in the Danger room. The conversation had somehow found its way to gossip about Erik, and the reasons why he left and what he had been up to in the previous ten years, and Storm had very casually said, "He had a family in Poland, I believe. A wife and a daughter."
"What?!" In a flash Peter leapt from where he had been wolfing down food at the barbeque pit to where Storm was sitting by the lake, giving her a fright when he suddenly appeared next to her even as he asked again, "A wife and a daughter?!"
"Oh," Storm said, clearly remembering belatedly his relation to Erik. "Yes," she said, before visibly hesitating.
"So that's why he left? To go back to them?" Peter asked, not sure how he felt about it.
"No, actually..." Storm trailed off, clearly reluctant to elaborate. He was dimly aware of Jean ushering everyone away, leaving them to talk in relative privacy.
"Tell me!" He urged again, when Storm took too long to answer.
"They're... they're dead," Storm finally replied. "I heard En Sabah Nur talk to Magneto about them. They were killed by the Polish police."
Peter, who had been leaning over Storm, fell back in shock and landed on his butt on the grass. "Dead..." he whispered, stunned beyond everything.
"Peter..." Storm said, awkwardly reaching out a hand to pat his shoulder. "I'm so sorry... I should have told you earlier."
Peter wasn't listening to her anymore though, lost in his thoughts. He had a younger half-sister, but she was gone before he even knew he had one. Too late, once again.
No. Not this time.
"Be right back," he said, and dashed off, ignoring Storm's startled shout when he suddenly disappeared.
The problem with having a sister who didn't want to be found was that it could be very difficult to find her. Pretty much impossible, when your sister was Wanda Maximoff.
But the advantage about having super-speed was the ability to check all his sister's usual haunts in just a few hours. At last he found her, at a place up in the mountains, deserted and isolated for miles and miles except for her.
He burst into her cottage, and practically yelled at her, "We need to use your powers to get our half-sister back."
Wanda didn't even startle, having had a lifetime's practice at growing immune to Peter popping up constantly, so she continued to sip hot chocolate from her mug as she marked her place in the book before closing it. She arched an eyebrow at him. "What half-sister?"
Everything burst forth in a torrent, and Peter rapidly brought Wanda up to date on the re-emergence of their father, his subsequent departure, and the discovery of their long-lost, now dead half-sister.
There were tears in Wanda's eyes when he finished, and she squeezed his fingers tightly. He didn't even realize that they had been clutching each other's hands. "You want me to bring her back?"
He nodded empathically, "You know you can do that!"
"No I don't. We have no idea what I can do at all!"
And that, in a nutshell, was why Wanda didn't want to be found, and why she kept herself isolated from civilization.
Peter's powers were well-defined. He had super-speed, and over the years they had tested exactly how fast he could go, how long he could go for, all the little tricks he could do with it. They knew everything there was to know about his powers. Not so for Wanda. Her powers of reality alteration remained random, undefined, and dangerously unpredictable.
"Well at least we know that it's something you've tried before," He countered.
"Peter," Wanda sighed, "resurrecting a dead bird is very different from resurrecting a person. I can't do it. What if it goes wrong? This is our half-sister we're talking about. What if I'm subjecting her to something even worse than death? I can barely control my powers. I can't just experiment on her and hope for the best!"
"But she's our half-sister! Wanda we have to at least do something!" He paced around the room, frantic, each circuit around the room getting faster and faster.
He suddenly remembered someone, and he stopped in his tracks, spinning around to face Wanda, grinning widely. "You can't control your powers. But I know who can teach you how to. Come with me."
He sped them both back to the school and straight into the Professor's study, dumping Wanda unceremoniously on the floor.
He startled both Charles and Hank, who had been deep in discussion over some school matters. "Professor, we need your help," Peter burst out. "Now!"
Charles studied him and Wanda with narrowed eyes, and Peter made a waving motion with his hands, encouraging the Prof to just read his mind and see what's going on. He felt a small tickle in the back of his mind as Charles did just that, and then Charles's eyes widened. He wheeled closer to Wanda, who by now had stood up from the floor and was curiously studying the room around them and its occupants.
"Allow me to introduce myself," Charles said. "My name is Charles Xavier, and I'm the headmaster of this school for mutants. Your brother has been here for a couple of months, and I'm very happy to finally meet you, Wanda." He held up a hand to forestall the inevitable question. "I am a telepath, and your brother just gave me permission to read his mind. That is how I know your name, and also your mutant ability - you can alter reality?"
Peter could almost feel Wanda's ire at him despite not having any telepathy of his own. 'You couldn't have given me a little more warning?' her eyes shouted as she glared at him, before she turned to answer Charles. "I guess reality alteration is the best way to describe it? Honestly, we don't know. I've never had much control of it growing up, and the things it allowed me to do had always been random and unpredictable. I... I can't control the results."
Peter couldn't take bear waiting anymore and interrupted their conversation. "Your job is to teach us how to control our mutations right? I've seen you training with Jean. You can teach Wanda too! Then we can use it to bring my half-sister back to life, and then our father will come back."
Charles looked completely shocked. "It's not that simple, Peter. Bringing the dead back to life..."
"But we can try! Come on! 'You never know your own potential until you try' - you always say that. I'm sure Wanda can do it."
Wanda nodded, looking a little nervous but no less determined. "If it can bring our half-sister back, I'll like to try."
And so it was decided.
It really wasn't simple. But it wasn't impossible. Their saving grace was the blood connection between Wanda and their half-sister, which meant there was at least a link between the two of them that Wanda could draw on. Or something. Peter wasn't very certain of the details, except that it involved Wanda being shut in with Charles for days and days as they probed at the limits of her power, while Peter paced uselessly outside. He had wanted to take part at first, but they had chased him out, saying that he was distracting, so he spent his days bugging the other X-Men and Beast and Mystique instead.
At last they were reasonably confident in Wanda's ability to resurrect their half-sister, and it was time to find the final piece, which Charles sent Peter to retrieve.
He found their father back in Poland, in the house that must have belonged to him and his wife and daughter. In a conversation as painful as it was freeing, Peter finally came clean about their relation to each other. Fast on the heels of that revelation was Wanda, her powers, and their efforts at finding a way to bring his half-sister (Nina, his father said) back.
Peter didn't do awkward reunions well, but suffice to say that there were tears and hugs, and he saw his father's face turn from anger and disbelief to fledging hope.
He brought Erik to the clearing where his sister - Nina - died. Wanda, Charles, and Mystique were already waiting for them there, Kurt having teleported them over earlier. There was a brief, very awkward moment as he introduced his father to Wanda.
Wanda knelt at the clearing and began invoking her powers, Charles at her side to help fine-tune her control. At her other side Erik gripped her hand, providing the memories and emotional base that Wanda was drawing on, their half-sibling connection not being strong enough to bring Nina back completely.
Wanda's power grew and grew as the wind picked up around them, scattering leaves around in a frenzy, and a red mist formed before them, eventually coalescing into a small form.
A little girl with long brown hair, rubbing her eyes blearily as she sat up and looked around the clearing. "Papa?" she asked, reaching out, and Erik cried out, crawling over to Nina and hugging her tightly to his chest as he sobbed.
Wanda gasped, staring at her hands in wide-eyed disbelief. "I did it?!" she whispered, and Peter fell to his knees beside her, and they clung onto each other. Eventually their father, with Nina in his arms, reached out to them, and the four of them huddled in a group hug together as everyone else looked everywhere else but at them.
Their family was finally complete.
Note: This fic was originally posted on AO3 as part of the Fandom Giftbox 2016 collection.
