"Filth! Mudbloods! Stains of dishonour in the house of my fathers!"

A piercing shriek cut through the previously quiet air like a butter knife. Tom and Jerry both clamped their hands down tightly over their ears. The former got up and made his way out of the living room into the hallway. It was just as he had expected. Somehow the curtains covering Mrs. Black's portrait had opened and as was usual when this happened, she was screaming the house down. Kreacher was already running down the stairs to see to it.

"Don't worry, Kreacher!" shouted Tom, trying to make himself heard over Mrs. Black's howls. "I'll get it." Red sparks shot out of his wand, a loud bang sounded, the curtains swung shut and Mrs. Black was silent once more. Tom headed back to the living room to find Jerry cautiously removing his hands from his ears, as if nervous that Mrs. Black might start again at any minute.

"Sheesh, I hate it when she does that" he said at last.

"I know" said Tom as he sat back down on the sofa. "And to think a nice guy like Sirius could have come from that old hag."

A sad silence fell over both Tom and Jerry in the wake of this sentence. They hadn't spoken about Sirius in a long time and now suddenly the memories of their fallen friend came flooding back to them. Jerry sighed and turned to the page in the photo album. On the overleafing page, amongst others, was a photo of Sirius taken in his younger days at Hogwarts. It was the full moon in the photo and he was transforming into his animagus form. Tom smiled and stroked the photo of the black dog, Jerry noted that Sirius was the only dog Tom had ever trusted and liked, and with good reason.

"He saved my life as a dog" said Tom, as he continued the stroke Sirius' photo fondly.

"And then we helped to save his, one time" said Jerry as the recollections came back to him.

It had been an eventful year at Hogwarts.

It had started off with the news of an escaped mass murderer by the name of Sirius Black escaping, along with Hermione buying a hideous cat named Crookshanks, who seemed determined to catch and eat Ron's rat, Scabbers, and wasn't always very nice to Jerry either. On a lighter front, Hagrid had been appointed as new Care of Magical Creatures teacher, and on his first lesson had brought along a hippogriff named Buckbeak. Of course it was all ruined when that jerk Draco Malfoy started insulting the hippogriff, despite Hagrid's warnings of what would happen if a hippogriff was insulted. As far as Tom and Jerry were concerned, the scratch that Buckbeak put on Malfoy's arm wasn't nearly big or deep enough. But Malfoy being Malfoy had squealed to his father, who had done everything in his power to get Buckbeak executed and had suceeded.

To shake things up even more, it had now transpired that Professor Lupin, the current Defence Against the Dark Arts teacher was actually a werewolf and a friend of Sirius Black. However it also turned out that while Black was indeed Harry's godfather, he had not betrayed their hiding place to Voldemort, who had in turn killed them, as was the popular belief. Instead the one responsible for that was actually Scabbers, or to call him by his real name, Peter Pettigrew. Pettigrew, like Black and Lupin, had been a friend of James Potter, Harry's father. This had made Sirius determined to find and kill him for his betrayal, which was the reason he had broken out of the wizard prison Azkaban.

Actually Sirius never got round to killing Pettigrew. At the last minute, Harry had stepped in and decided to give him up to the dementors, the guards of Azkaban who had been stationed to guard the school while they hunted for Black. Tom and Jerry agreed that this was certainly a well deserved fate for Pettigrew. They had had experience with the dementors, just being in their prescence was enough to give one a depression powerful enough to fell like throwing oneself off the astronomy tower. And that was nothing compared to the terrible memories they brought back into your head. In Harry's case it had been hearing his mother's screaming voice just before she had been killed. In Tom and Jerry's case well...they didn't really like to think about it.

Right now they were dragging Pettigrew kicking and screaming up to the Hogwarts castle, Lupin and Ron were chained to him. Harry and Sirius had gone off a little way to talk, and Hermione, Tom and Jerry were bringing up the rear.

"Gee, I'm glad this whole thing worked itself out" said Jerry. "I mean, now that we caught the real betrayer of H.P's parents, Sirius' name will be cleared and the Ministry of Magic will have to get rid of those god-awful dementors. Man, I'll be glad to see the back of those things."

"Me too" said Tom. He looked up at the sky. "Oh, and its a full moon tonight as well, how nice."

Herminone stopped dead in her tracks, she turned around and faced Tom with a look of shock, as if he had just said a very rude swear word.

"What?"

"I said there's a full..."

And then Tom remembered, Professor Lupin was a werewolf, and at the full moon there was only one thing that could happen. It was already happening, Lupin's body was being wracked with violent contractions, like he was having an epileptic seizure. As that was happening his face was becoming more elongated, more wolf like. Coarse hairs started sprouting all over his body, and his arms and legs were becoming thinner and longer. To complete the transformation, a short, bushy tail sprouted out of his rear end. Now a fully fledged werewolf, he tried to free himself of the manacle binding him to Ron and Pettigrew.

Lupin wasn't the only one who would be transforming tonight. Tom saw whiskers sprouting from Pettigrew's face and his already rat-like face was becoming even more so. The mousy hair that covered a few patches of his head was now once again spreading to all parts of his body. On top of all this he was shrinking so that soon his wrist easily slipped out of the manacle. Soon he was scurrying away through the grass as a rat.

"Oh no, you don't!' bellowed Tom. All those years spent chasing Jerry came back to him. He got down on all fours and tore after Pettigrew, ignoring Jerry and Hermione's cries. Pettigrew's bald tail was just within inches of Tom's grasp when suddenly he tripped over one of the Whomping Willow's roots. Pettigrew vanished into the darkness and a shadow fell over Tom, blocking out the moonlight. He looked up and saw to his horror that Professor Lupin was standing over him as a werewolf, his jaws dripping with slaver. He raised one clawed arm and prepared to strike.

Suddenly something huge and black slammed into the werewolf's chest and sent him flying backwards. Tom saw Sirius in his animagus form of a big, black dog. He was snarling at the werewolf with his hackles raised. Professor Lupin for his part was down on all fours and snarling at the dog, as if he didn't know it was his best friend. Suddenly the two animals tore at each other. The dog clamped its jaws around the werewolf's shoulder, the wolf howled in pain and clawed at the dog in a vain attempt to dislodge him. As both of these animals were people he knew and cared about, Tom wasn't sure whether he should cheer for Lupin or Sirius.

Finally though the werewolf threw the dog off him and galloped off into the forest. Apparently he had decided Harry, Ron, Hermione, Tom and Jerry were more trouble than they were worth. For a while the night air was silent, then from down by the Hogwarts lake there came the yelp of a dog in distress.

"Sirius!" cried Harry and dashed off down the hill, Hermione followed.

"Oh man, what now?" gasped Jerry. "That boy is gonna get himself into trouble again, I just know it."

"Well, that's what our job is all about, isn't it" said Tom as they hurried off after Harry and Hermione. "Getting him out of it."

As they neared the lake, Tom and Jerry felt that all too familiar cold feeling of depression come upon them. There were dementors nearby. As they reached the thinning trees by the lake shore, Tom and Jerry saw that there were hundreds of thousands of them circling in the sky above. Directly below them, crouching on all fours as a man, was Sirius. He was holding his arms up and moaning pitifully.

"No, no, nooooo" he moaned. "Please, I'm innocent."

But the dementors took no notice, they glided slowly towards Black, as if to prolong his torturous misery. Tom and Jerry watched as Harry and Hermione pulled out their wands, Harry told Hermione to think of something happy, but how could anyone do that with so many dementors nearby?

"Expecto Patronum!" bellowed Harry. A silver light erupted out of his wand and formed a sort of shield around him and Sirius. The dementors drew back, afraid of it. Hermione collapsed next to Harry.

"So that's the spell to keep dementors away" said Tom, trying to block out the bad memories that came flooding back to him in the dementors prescence.

"We...we gotta help them" said Jerry, who was also threatening to drown in a sea of depression. He and Tom made their way towards the dementors, who looked at them when they sensed the new arrivals.

'Tom, Jerry, get back" said Harry in a weak voice.

"No way, H.P" said Jerry. "We're not letting you face this alone." He took out his wand and shouted the spell.

"Expecto Patronum!" A small silver light appeared at the end of Jerry's wand, but flickered out soon afterwards.

"You-have-to-think-happy....thoughts" said Harry, every word an effort as the dementors sucked the will to fight from him.

Jerry closed his eyes and battled desperately against the bad thoughts that were filling his mind. He thought of the times he had gotten Tom in trouble before they had met Harry. But somehow that didn't make him as happy as it used to now that Tom was his friend. He thought of the night he had defeated the troll in Harry's first year, again that did nothing to help.

Tom was also thinking such thoughts, but with little effect. All the while the dementors were coming closer and closer. Finally, Jerry thought of the one thing that never failed to make him happy, not once. A huge hunk of gorgonzola cheese came into his mind, towering above all the other cheese. Jerry lifted his wand and cast his spell.

"Expecto Patronum!"

The effect this time was drastically different to the last. A silver beam of light erupted from Jerry's wand and shot out amongst the dementors, who fell back in horror at the sight of it. The light buzzed through them for a while before it sprouted a long, tuft ended tail, four padded paws, and a bushy, silver mane. Soon it was a lion that was charging through the crowd of dementors, roaring loudly as he did so.

The sight of this magnificent silver creature holding back the dementors filled Tom with awe and wonder, and now he too cast his spell.

"Expecto Patronum!"

Silver light shot out of Tom's wand too, before sprouting a hooked beak and two enormous wings. The eagle patronus joined the lion in their battle against the dementors, who were now jostling to get away from them. Some were speeding away towards the other side of the lake. Tom and Jerry wached them go with great satisfaction. At last they were winning the battle, they were protecting Harry, they were doing their job.

Suddenly Tom spotted something out of the corner of his eye, he turned and almost screamed in horror at what he saw. Sirius was now lying unconscious with Hermione, Harry was on his knees looking up towards the sky. Hovering just above his face was a dementor who had apparently decided to take its chances with the patronuses. It lifted back its hood to reveal a shapeless face that looked nothing like any sort of face Tom ever had or ever would see. Where its mouth should have been there was only a dark, circular hole, making a rattle like snot in a blocked nose. Tom knew what it was going to do, he and Jerry had overheard Professor Lupin telling Harry about it once. This was the dementor's kiss, it was going to suck out Harry's soul.

"No!" bellowed Tom. He directed his wand at the dementor, his eagle patronus folded in its wings and dived right for it...only to be stopped as another dementor flew straight into its path. The eagle was forced to hover for a few, precious moments while it saw off the dementor. In those moments, the dementor attacking Harry lowered what passed for its mouth to Harry's.

At this point Tom felt the despair flood over him again. His patronus and Jerry's had seen off many dementors but what did that matter when there were a thousand more to replace them. And now one of them was going to suck out Harry's soul and leave him a brain dead zombie. As another dementor appeared in front of him, Tom's eagle patronus vanished.

"No, get away from him!" shouted Jerry, directing his wand at the dementor in front of Tom. It glided towards him and revealed Harry being attacked by the other one. The same despair that had snuffed out Tom's patronus like a candle now began to engulf Jerry, he could no longer think straight. All he could think about was the dementor that was threatening to suck out Harry's soul, and the one that was gliding ominously towards him. The silver lion vanished and the dementors closed in for the kill.

"Expecto Patronum!"

The loud bellow that sounded from further along the lake caught the attentions of every dementor present. Another patronus, a stag this time, came galloping across the surface if the water, its antlers lowered and poised for the dementors. They moaned in horror at the sight of it and glided desperately away. The stag's antlers caught the hood of one dementor, it writhed about wildly before freeing itself and soaring away with its companions. Soon, every single dementor was gone from the lakeside. The stag walked back in the direction it had come before vanishing.

At this point, Harry fainted. Tom and Jerry tried to get a good look at their saviour, but before they could do so, they too lost consciousness.

"Professor, Black's innocent!"

"It was Pettigrew, he transformed into a rat"

"You have to believe us!"

These were the frantic words that Harry, Hermione, Tom and Jerry were saying to Professor Dumbledore. They had woken up in the hosptial wing and had just heard the news that Sirius had been captured, was being held hostage in Professor Flitwick's office and was awaiting the dreaded dementor's kiss. Nobody had believed their claims of Sirius' innocence, and now even Dumbledore was holding up his hand to silence them.

"I do believe you, all of you. But I'm afraid the word of two thirteen year old wizards and a cat and a mouse, however honest and true, will not convince anyone who has listened to the word of a whole street of witnesses who claim Black's guilt."

"But...Professor Lupin..." began Tom.

"Professor Lupin is currently deep in the forest, Thomas, unable to tell anyone anything. By the time he is human again, it will be too late. Sirius will be worse than dead." He paused for a moment before going on.

"What we need is a little more time." He turned to Hermione. "Three turns should do it, Miss Granger" And he headed out of the hospital wing.

What Dumbledore mean by 'three turns' Tom and Jerry would not find out right now. They both had something on their minds which they wanted to discuss with Dumbledore, and they followed him out of the hospital wing.

"Professor Dumbledore" they cried in unison. He turned to face them.

"Yes?" he said in a patient voice. Tom hung his head and spoke first.

"Down by the lake, when Harry was being attacked by dementors, me and Jerry, we...well we tried to use 'expecto patronum' against them. And it worked, it really did."

"But one of them got past us and tried to suck out Harry's soul" said Jerry. "And when we saw that we just couldn't hold out. Our patronuses vanished. If it hadn't been for that other patronus then...well...you know."

"What we're trying to say, Dumbledore, is that we're sorry" said Tom sorrowfully. "We failed to protect Harry, we're not fit to be guardians." Dumbledore bent down to Tom's eye level.

"It may please both of you to know that you are entirely wrong" he said softly. "There are two reasons for this. One is that it is extremely hard for even the greatest of wizards to cast even a remotely effective patronus with so many dementors about. The fact that you to were able to cast one at all is a great feat indeed. The second is that while your patronuses may have vanished at an inappropriate time, that does not mean that you failed to protect Harry completely. If anything you helped by him time by keeping the majority of the dementors away. Had you not done so I very much doubt that he would have held out long enough to be saved by the patronus your saviour cast. Neither of you has any need to be sorry."

"Thank you, Professor" said Tom in great relief.

"Anyway, there will eventually come a time when Harry will have to fight his own battles" said Dumbledore. "I'm afraid when that time comes you won't always be there to protect him."

"Yeah? Well we'll try" declared Jerry. Dumbledore smiled kindly.

"I can see why your patronus is a lion, Jerry. You have a brave heart indeed." And he turned and headed off down the corridor.

"Professor" Tom called after him. "Do you know who it was who cast that other patronus?"

"No" said Dumbledore. "But I believe Harry might be able to tell you when he and Miss Granger return. In fact if you look out the window I think you'll both see something that pleases you."

Tom lifted Jerry on to his shoulder and they both did as they were told. At first they could see nothing but the full moon and the Hogwart's towers. Then, on the battlements they noticed movement, and what they saw made them gasp with shock and amazement. There on the battlements was Sirius, free and sitting on Buckbeak, Buckbeak back from the dead! Harry and Hermione were standing next to them, Sirius spoke to them in words Tom and Jerry could not hear. Then Buckbeak reared up and took to the skies, his sillouette well made out against the full moon.