Author's Note: And we're back! If you've got time, I'd recommend reading a little about Walpurgisnacht on Wikipedia or something similar; it will give you an idea of why the Death Eaters chose this day. But it's not at all essential to understanding the story.

It was April 30th, and time for me to break out my father's Invisibility Cloak for the first time since my first day in this time. I sent Ginny to breakfast without me, saying I was too ill to eat; as soon as she left, I began packing for my looming departure. When I'd stuffed everything into my satchel, I left a letter along with the crystal ball necklace under Ginny's pillow, grabbed the Cloak, and set off to find Harry.

Somehow Hermione had managed to convince Harry and Ron to attend their classes that day regardless of what would happen that evening. Since Harry and Ron shared all their classes, this made it difficult for me to catch Dad by himself, but when Ron took a trip to the bathroom during their break between Potions and Defense, I hunkered down by Harry, whispered, "It's Susan; follow me to the Room of Requirement," and tugged on his sleeve. I saw his eyes go wide, but he followed me up to the seventh floor.

Inside, I flung off the cape. "Harry, we need to talk," I said.

"You nicked my Invisibility Cloak?" he said, sounding annoyed.

"Not exactly," I said. "If you let me explain, it'll all become clear. Please, sit down."

We both sat, and I drew in a deep breath. "You must promise me that whatever I say, you won't leave this room."

He frowned. "All right, I promise."

I paused for a moment. How to explain after all these months? "Harry, I'm not really Ron and Ginny's cousin."

His eyes widened. Before he could burst in, I finished the thought: "I'm your daughter. I'm a time traveler."

"Susan, this isn't funny," Harry said, and his voice was tinged with panic. "Voldemort is coming here tonight. We can't waste time on practical jokes."

"It's not a joke. All that Seer stuff was a cover for the fact that I'm from the future and I knew everything already."

His mouth moved a few times without making a sound. "It's bollocks."

"It isn't. You remember how you thought I might be your mum? There's a reason I resemble you."

"You don't look anything like me."

"Harry, I don't know what I can tell you that will convince you. All I can tell you is that some time in the past month, you and Ginny . . . well, conceived me."

Harry went a horrible shade of grey. "Oh no."

I grinned. "It's all right! Molly and Arthur won't be angry."

"I think I'm going to be sick," Harry said, putting his head between his knees.

I patted him on the back. "It's okay, Dad. It's okay."

"DON'T call me Dad." Then his head shot up again. "Wait a sec. Why are you telling me this now? Why not months and months ago?"

"I had to help you through the destruction of the Horcruxes. I've almost completed my task, so I'll be going home any moment now."

"But that doesn't -- why did you come here under false pretenses??"

"If you or Ginny had known that she'd fall pregnant this April, I wouldn't be here to tell the tale," I said sardonically. "You might've been a bit more careful."

"We used -- it was just this one --" He groaned in frustration. "What am I going to do?"

"You? You're going to defeat Voldemort."

He looked at me swiftly. "You're from the future."

"Yes."

"A future in which I've already defeated Voldemort."

"Yeeees . . . ."

"Why don't you seem sure?"

"Well, I believe that's what will happen. But no one actually sees you defeat him."

He squinted and thought about that for a moment. Then he went white. "I die. I'm dead."

"No, no, I'm here to make sure that doesn't happen," I said soothingly. "I have a plan."

"You have a plan." He laughed, sounding a bit unhinged. "My -- my time-traveling bastard daughter from the future has a plan about how to retroactively save my life."

I drew back a little. "No reason to be cruel," I said, hurt.

"I'm sorry, Susan, but you must admit that this sounds INSANE."

"Try living in the past with your teenaged parents for a year," I shot back. "Then tell me what 'insane' really means."

He glared at me. "So what's this brilliant plan?"

"Before I tell you, I have to tell you two things first."

"Yeah?"

"First of all, the future is immutable. Anything I know can't be changed."

He narrowed his eyes. "I don't like the sound of this."

"Secondly, in my future, you've been missing since . . . well, today. This very moment, in fact."

He jumped up. "No."

"Yes."

"I'll -- I'll leave right now!" he cried, wild-eyed.

"No you won't," I said quellingly. "Because you don't. You didn't, and you won't."

"Don't I have free will?" he raged.

"Yes and no," I said. "You do disappear now; that much is certain. But since no one but you knows the circumstances of your disappearance, it could be that you just take your Invisibility Cloak and go traipsing off to South America. Or you could go into Moaning Myrtle's bathroom and entomb yourself in the Chamber of Secrets. I'm trying to give yourself an opportunity to defeat Voldemort and -- eventually -- make it back to me and Mum."

He sat down slowly. "What's your plan?"

"You remember Hermione's lesson when you were in the Hospital Wing, right?" He nodded dumbly. "I want to hide you with Fidelius."

"But -- that'll break if you even look at me." When I shot him an incredulous look, he retorted, "Yes, I do listen to Hermione."

"I'm impressed. Here's what I'm thinking: I'll hide you with Fidelius, then I'll return to my own time straight away."

He stared off into the distance, thinking. "Then . . . I could duel Voldemort, and he wouldn't even be able to know who or what was weakening him."

I grinned. "Exactly."

"And I'll defeat him. And then what?" He looked back at me. "Then I spend the rest of my life being invisible to every other human being on earth?"

"Until I return to the future," I corrected. "Then I'll break the spell."

"How long will that be, exactly?"

"Eighteen years."

Harry stared off again, and then without warning, he put his head in his hands. I suspected he was crying. After a minute, he spoke thickly: "I didn't even get to say good-bye."

I put a hand on his knee. "I know. I'm so sorry. I couldn't risk anyone suspecting this. I don't know if it would work if they did."

"Ginny's going to be raising my child by herself, and Ron and Hermione will -- they'll feel guilty the rest of their lives!"

"Harry, the three of them SENT me here. They've had hope, all these years, that I would bring you back with me."

"Can't you do that?" he asked, looking at me with shining eyes. "Just take me with you?"

"Too risky," I said. "If you didn't manage to come, you'd be stranded here. And then you'd have to die for the future to be right. I'm trying to make sure you end up alive, Dad."

He didn't object this time to the moniker. "This is too much," he mumbled.

"I know," I said. "But I think we should get it over with."

"What, now??" he said.

"Harry, there's no time. They'll have noticed you're gone by now, and they'll come and look here soon enough."

"Isn't there another way?" he moaned.

"I've turned it over and over in my head. Hermione's been thinking it over all my life. This is it, Dad."

He squared his shoulders at that proclamation. Then he stood, and I followed suit. To my surprise, he reached out and hugged me to him. "I'll see you in eighteen years," he said.

I smiled a little sadly. "Be strong," I said. Then I stood a few feet away from him and began weaving the spell. It was entirely nonverbal, and I began by visualizing what I had to hide: Harry, Harry, Harry. I thought about him, his mussed black hair, his Coke bottle specs, his eyes that I'd inherited. Then I thought, "Fidelio," and I felt the hum of magic in the air that meant the spell had taken hold.

"Oh, that felt queer," he said, and examined his hands and arms. They looked normal to me; I wondered how they looked to him.

Just then, I heard a frantic knocking at the door and Mum's voice: "Harry! Harry, are you in there?"

Harry looked at me in mute anguish; I fumbled in my satchel for my Time Turner. "Harry, we're going to come in," came Hermione's voice, much calmer than Ginny's.

I only had a moment: I ran to Harry, gave him a filial kiss on the cheek, looped the Time Turner round my neck, seized it by the round metal top, and dashed it against the high wooden table that had suddenly appeared by my right hand. (This was, after all, the Room of Requirement.)

"What was that noise?" I heard Hermione ask Ginny, and then I felt as though I'd been speeding along on a racing broom and had suddenly braked without slowing first. I was flung headlong out of my parents' time, but I blacked out long before I could say with any certainty just which time I'd landed in.