The group waved goodbye to Draco at the train station. The Granger's home had been completely charmed with as much protection as the Weasley's The Burrow upon returning from the disastrous tournament. Severus even added some of his own nastier charms that were keyed to most Death Eaters he knew and the recently discovered Peter Pettigrew.

As the train took off, Hermione sighed, "What a break…"

Neville nodded, "That sure put a damper on our summer,"

Harry recalled how they had come out from hiding when Arthur with Neville's cousin, Nymphadora Tonks, and a man that Luna recognised to be her father, Xenophilius Lovegood, had returned calling into the woods with the Weasley patriarch as pale and worried as they had never seen him. In fact, Severus even appeared at the camping site with Albus in a burst of phoenix flame, looking sickly pale. He had immediately run a scan on Harry and later his friends. He had reported to feeling a tingling on his Dark Mark and when the Arthur reported to Albus about the disturbance via Patronus, as was the procedure during his time as an Order member out of habit, they both had grabbed onto Fawkes. Severus of course was immediately attacked with suspicion until both Albus and Arthur stood up for him.

That aside, the summer was filled with studying history and spells leaning on both defence and offence. Of course Draco can only help on the research part. They had collected at Severus's home in a week long sleep over after a few days returned from the tournament until their fourth year letters arrive.

The train ride was uneventful and when they finally reached Hogsmeade Station, the group of friends immediately took a ride in one of the carriages. Neville looked at Hermione, "I'm glad your parents still allow you to come to Hogwarts, Hermione. After what happened, I was so sure that they will pull you out,"

Hermione smiled, "It was thanks to Draco and Prof Snape and Prof McGonagall. Not to mention, despite the danger, they know that I'm in good hands. Draco managed to convince Mom that the attack is more the reason for me to come to Hogwarts, to learn how to protect myself and them,"

Ron nodded, "It's only logical…"

Harry added, "Is it just me or does Hogwarts look extra magical tonight?"

They climbed out the carriage and noticed what Harry meant when they set their eyes on their magical school. True enough, the air felt different although to Harry it felt like there were shimmers in the air like when someone played with too much glitters. Cedric, who just passed by stood next to Harry, "Hmm…now that you mention it something felt…I don't know, cleaner?"

Hermione scrunched her face, "Did the Headmaster run an exorcism on Hogwarts during the break?"

Ron looked at her, "Why would he do that? And what's exo-scissor anyway?" At that the others took it as their cue to leave Ron to Hermione's lecture about exorcism. Neville shook his head, "Seriously, even I have heard about exorcism," The other snorted and snickered while Harry shook his head at Ron's silliness.

The Welcoming Ceremony ran through as usual until the Albus stood up and started a speech about a Triwizard Tournament. Harry felt a chill ran down his spine and wondered about that until his eyes met with that of an odd man on the Head table. He noticed how Severus looked more blank than usual and decided that it means something that Severus was having a hard time being easy about something. His extra blank face usually means that he has his guard up more than the usual perceptiveness.

Harry turned to Blaise who had been taking a seat beside him since last year, "Who is that?"

Blaise looked up at Harry's quiet enquiry, "That man? He's Mad-Eye Moody, ex-Auror and was rumoured to be the reason that most Death Eaters were locked up tight in Azkaban," He added with a murmur, "Supposedly he's the new DADA's professor,"

True enough just before the closing ceremony as was usual, Albus introduced Mad-Eye as their new professor for this term's DADA class. Once they were sent off to their dorms, the Slytherin noticed that the new professor was standing near their path to the dungeon. As Harry passed the man by, his instinct screamed at him 'wrong'. He whipped his head to look at the man who was also watching him with his fake blue eye. He wondered why he felt so because the last time he felt that way it was with Quirrel and again with Ron's pet rat that turned out to be Pettigrew.

Class started as usual but the students were excited about the prospect of other magical schools coming to their school. Moody first class of the year started at the end of the week. He sat at his table, eyeing the Slytherin and Hufflepuff as they filed into their class. He barked, "Alright, to your seats!"

He lined on his table three jars of rather large daddy long legs. Neville frowned and scooted closer to Harry, already disliking the class. He has a strong feeling that he won't like what comes next. True enough, Moody started the term with a round of the Unforgivable Curse. He sneered at the class, "Alright, can any of you list the number of the curses that will sent your straight to Azkaban?"

Nott snorted, "Everyone knows that. There're three,"

Moody made a face at the boy, "Two points for the cheek and one point for the answer. Never say that I am not fair," Nott gaped at the points with a scandalised look. Moody ignored the Slytherin prat and looked around, "Anyone knows the name?!"

They looked at each other nervously and Blaise raised his hand. Moody nodded at the Latin boy who answered, "I heard about one; the Imperious Curse,"

Moody didn't elaborate, simply took out a spider, enlarge it and cast the curse, "Imperio!" He made the spider to first dance and made macabre acrobats, eliciting laughter from the class. He barked, "CONSTANT VIGILANCE!" This shocked the class into silence.

He eyed them like a hungry predator, "Think that's funny, do you?" Instead of nodding, the class looked nervously at each other as if realising that something wasn't right. Harry and Neville had stared at the spider, pity in Neville's eyes. Harry simply tilted his head before saying, "Complete control…against their wish…"

Moody turned to him and their eyes met. The professor nodded, "Correct…troublesome business. Hard to tell who's being controlled and who's willing servant…"

He looked at the others, "The Imperious Curse, a curse that force you and allow the caster to make you do anything," He forced the spider toward a fishbowl filled with water, "I can make it drown…" He forced the spider to march to the window, "I can make it jump to its death," He then march the spider to Blaise, "And I can make it kill…and it will do this all in complete euphoria despite knowing that what it does isn't something it will normally do…except for the biting…"

The class gulped, Neville's face set in a frown as that unsettling feeling growing stronger. Harry looked at the boy, sensing his turmoil. Moody then continued, "CONSTANT VIGILANCE! But…there is a way for the curse to be lifted…" He looked into the student's eyes, "Strength of will…you can throw the curse off as long as your will power is stronger than the caster," That said, he returned the enlarged spider back to its original size and return it to the jar it was from, the curse lifted.

He enlarged the next spider while asking, "Anyone else know the second Unforgivable?"

Neville answered with a carefully blank look but Harry can feel something like dawning despair and desire for knowledge at war inside him, "The Cruciatus Curse,"

Moody looked at the boy, "Ah…yes…the torture curse. As the name suggest, an excruciating curse…for both the mind and the body," He casted the spell, "Crucio!"

The usually silent creature actually managed a sound similar to a very high pitched scream of pain and terror had it been human. Neville become paler and looked positively sick. Harry scowled and growled, "Enough!" His voice echoed unnaturally and the room dropped in temperature enough to fog the windows. He does not like the pain and guilt that was biting at Neville's conscience.

Moody stopped, more in shock than because he wanted to. He looked at the strange boy with the long silver hair. He could tell that something was wrong with the boy, something dark and inhuman. He returned the spider back to its normal size. Harry noticed disappointment in the man's eyes and wondered at that for as he had casted the spell, he was sure there was a glint of glee.

Moody cleared his voice, "As you can see, there was nothing else to tell about the curse,"

The class fell silent as they waited for the next curse to be named. Harry coolly gave the name without being asked, "The Killing Curse…"

Moody looked at the pale boy and nodded, "Correct, the unstoppable curse. Before I get to that, the main reason for why these curses are 'unforgivable'. It is named such because it unforgivable CONSTANT VIGILANCE!" He barked out suddenly, shocking the students once again before continuing, "It is unforgivable because there no other reason behind the will of each curse. For the Imperious Curse, one must desire a strong will to overpower the will of another, to force them to do one's bidding even if it means death to the victim,"

"For the Cruciatus Curse, one must desire to hurt, to torture not out of necessity but out of the pure desire to see their victims in pain and to enjoy it," He hissed at them before leaning back, straightening his back, "CONSTANT VIGILANCE! And that being said, even if you cast any of the curses at me, without such desire behind the curse I won't even feel a tingle. Perhaps a tickle from the Cruciatus but nothing else,"

The students shared another uneasy look. This class seemed to be one filled with unease, even with children whose parents were suspected Death Eaters. Once satisfied that the children realised why the spells were unforgivable, Moody continued, "Now…the final curse…one that has only one record of survivor, two if you add the late Harry Potter. That child sat right before me," His eyes, both of them, swivelled to land on Neville.

Neville shifted in his seat, uncomfortable by the dark reminder. Moody turned on the last spider and before anyone could protest, cast the Killing Curse, "Avada Kedavra,"

It was softly spoken, unlike the other forceful and energetic casting of the other two. Harry sensed a shift in the air and literally felt the soul of the spider leaving its body behind. He realised then the other reason for the last spell to be so forbidding.

As Moody ended the class after reprimanding the students that it was he and not the bell that dismissed them, Harry looked behind at the dead spider and then at the suspicious teacher. Harry knew unhinged, Harry knew insane and Harry knew drop dead psychopaths.

Moody strikes him as the last and third type. This was decided after he cast the final spell. He didn't explain it fully but Harry's Dementor instinct answered the basic of the Killing Curse as clear as the summer sky.

To purely desire the death of another, that was the basic for the Killing Curse. Not out of anger, not out of a mistake. It wasn't like accidentally pressing the trigger when surprised or scared. It wasn't out of order. There was no such thing as being forced to kill when using the Killing Curse. It was as simple as the way the word for the spell was whispered; because they want to.

But there was a darker side to the curse that Harry suspected even Moody didn't realised. Soul is magic and magic is soul. There are no purer magic than the magic of the soul. The Killing Curse was ultimately a sadistic magic ritual encroaching necromancy. It was disturbing and disgusting even for Harry whose whole life was surrounded by similar magical creatures. And he supposed Voldemort knew this thus the name Death Eater.

The soul of the spider wasn't forced out but was sucked in…sucked into Moody's soul magic, literally devouring the other's magic…