Near the end of the school year, we suddenly saw that Hogwarts was no longer going to be the safe place it had been up until then.  The Dark Lord was advancing on Hogwarts, bringing with him an army of Death Eaters and other disgusting creatures like giants, acromantulas and dementors!  The defenders began erecting a magical barricade, but they warned everyone that the barricade wouldn't hold off the enemy for long.  "It will if many of you cast the same spell at the same time and place," Luna announced.  "We've been practising teamwork since our first year here and it makes spells stronger.  We'll be outside the barricade, though.  I think I know a way we can stop this battle before it starts, but I'll need your help."  She whispered something to Kingsley Shacklebolt and he nodded.  Then she explained to me the plan she had conceived and the part I was to play in it.  I protested that it was a risky plan and I wouldn't always be able to protect her, but she was adamant, and after some hesitation I agreed to go along.  I transfigured myself into my bonobo form and the two of us left the vicinity of the castle, armed with our wands, and stopped just outside the area where the barricade was being erected.

The nearest Death Eaters bumped up against the barricade and were stopped in their tracks.  The Dark Lord and all his Death Eaters threw every spell they knew at the barricade, but it held firm.  One of them spotted us, grabbed Luna and yelled, "I've caught one of the students, my Lord.  We can use her as a hostage."  He dragged her over to the Dark Lord, while I followed behind, ignored by everyone and everything around me.

"Well, well, look what we have here!" sneered the Dark Lord.  "We tried to kidnap you on the Hogwarts Express to shut up that crazy father of yours.  You got away from us then, but now you foolishly walk right into our clutches, and at a most convenient moment for us, too!  Did you think we'd be too soft-hearted to use you as a hostage to make the Hogwarts defenders lower their barricade, or did you think your pet ape could stop us by hitting us all over the head with that stick?"

While the Death Eaters were laughing at the Dark Lord's joke, I pointed my wand at him and applied all my willpower to cast the Obliviate curse non-verbally at him and then immediately cast Protego around myself and Luna.  He fell onto his back.  Bellatrix, who had been looking at him with love in her eye, rushed over to him and said, "Are you all right, my Lord?"

"Am I a lord?" he asked, staggering to his feet, breaking his wand and throwing away the pieces.

"What did you do to him?" she screamed, pointing her wand at Luna.

"I made it possible for him to love you," replied Luna.  "All you have to do is tell him that you're his lover and kiss him.  It'll be imprinted on his mind."

"This better work or I'll torture you into insanity!" Bellatrix growled at Luna.  Then, turning to the Dark Lord, she said softly, "Did I say 'my Lord'?  I meant 'my lover'."  And then she gave him a passionate kiss on the lips.

"Well, Darling, let's get away from this crowd," he said, looking at her with hearts in his eyes.  "I'd take you home with me, but I don't remember where I live."

"Oh, my poor baby!" she said.  "Come with me.  I'll lead you there."  With that, the two of them pushed their way through the crowd of Death Eaters and creatures, holding hands and kissing each other every few steps.

The Death Eaters nearest to us pointed their wands at Luna, but before they could cast any spells,  one of them - Severus Snape - declared, "Okay, folks, the party's over.  Let's go home.  Even if we could get through that barricade, we could never defeat the defenders of Hogwarts.  They still have an inspirational leader and we no longer do."

"If we just give up, how are we going to stay out of Azkaban?" asked one of the Death Eaters.

Snape was uncharacteristically silent, but Luna announced, "I spoke to Kingsley Shacklebolt, who will soon become the new Minister for Magic, and he promised that if you stand down now, tell the truth to the Wizengamot about what you did and why you did it, and never commit another crime, you will be pardoned."  Most of the Death Eaters began leaving the area, leading the creatures away with them, and the holdouts, seeing how few of them there were, reluctantly followed them.

At the trial, Death Eater after Death Eater confessed and was pardoned.  The last of them to speak was Snape.  "I joined the Death Eaters to wreak revenge on two Gryffindors who had bullied me during our student days," he said.  "But when the Dark Lord murdered the only woman I ever loved, even though he could have got everything he wanted by Stunning her instead, I was so furious with him that I switched sides and worked for the Order as a spy against him and the other Death Eaters.  Of course, I did have to do some evil deeds to avoid blowing my cover.  And yes, I did murder Albus Dumbledore – on his request.  The Dark Lord had ordered Draco Malfoy to kill Dumbledore, threatening to kill Draco and his parents if he failed, and to protect Draco, his mother insisted that I make an Unbreakable Vow to do the deed if he failed, which he did.  If I had broken the Vow, I would have died instantly, and Dumbledore, realizing that he was by then too weak to be of as much use to the Order as I was, ordered me to kill him.  It was my Patronus that led Harry Potter to the Sword of Gryffindor, which he used to destroy one of the Dark Lord's Horcruxes.  I wish to apologize to all the people I hurt and I beg the Wizengamot to pardon me."

Just as the Wizengamot was preparing to adjourn, Sirius got up and took the stand, surprising everyone present, and said,  "In most conflicts, atrocities are committed by both sides, and this one is no exception.  I was one of the two Gryffindors who bullied Severus Snape, and worse, I am guilty of attempted murder.  When he started spying on our werewolf friend, I tried to eliminate him by exposing him to the werewolf, and it was only the interference of the other bully that saved him.  I wish to apologize to Severus for my unconscionable behaviour and I beg the Wizengamot to pardon me."  As the Wizengamot finally did adjourn, the two former enemies shook hands, embraced and left the courtroom with their arms around each other's shoulders.

Life in the wizarding world returned to normal.  Neville Longbottom killed the Dark Lord's snake Nagini, which contained one his Horcruxes, and Hermione exorcised the last Horcrux – the one in Harry's forehead – which she was able to do without killing him because it had flown there instead of being put there with a magic spell.  With the Ministry now in good hands, I finally registered as an Animagus.  At the end-of-year feast, Ravenclaw was awarded the House Cup, thanks mainly to our having prevented the Battle of Hogwarts from ever happening.