The Order met again a week later. The hard-faced man was back, and looked forbidding in the parlor doorway as Dumbledore introduced him.

"It is my great honor," Dumbledore began with the usual overblown courtesy. "To introduce to you an esteemed member of the Department of Magical Law Enforcement. Alastor Moody is a former student of mine and an excellent Auror." Dumbledore paused for the inevitable ooh.

Aurors were thought to be very glamorous and dangerous, due in large part to a weekly radio program called Level Two that featured them as hard-boiled, no-nonsense daredevils with a penchant for bending the rules. Moody—with his voluminous black jacket, multitude of scars, and unshakable glare—looked like he'd been shaped directly from the airwaves.

"Alastor has offered his services to our cause, particularly when it comes to the necessary defenses we will require. He has much experience in these matters, and you would do well to listen to his advice." With that, Dumbledore settled himself in an intricately carved chair covered with models of dragons and unicorns.

It was surprising to see a Ministry official risking his job to be part of an underground resistance. But then, Dumbledore was a member of the Wizengamot, wasn't he? Peter wondered what he'd have done if he'd had as much to lose as Dumbledore or Moody—a ministry job, the risk of angering the highest magical authority in Britain. Would it be worth it just to play spy with his mates?

Auror Moody's gruff voice pulled Peter back to the matter at hand. "All right. Dumbledore's told you most of the particulars. I've been with the Ministry for about fifteen years now. It hasn't been a picnic, but when you're doing the important work you don't mind so much. Some of you may know Frank and Alice Longbottom." He gestured to the brown-haired couple Peter had seen at the first meeting.

"Those are the Longbottoms?" James whispered. "Don't look as impressive as I imagined. They're supposed to be bloody brilliant. They graduated Hogwarts in our first year."

Peter looked more closely. The girl, Alice, was petite and round-faced, and Frank was very lanky and wearing a knitted waistcoat. Both were smiling brightly—neither looked particularly strong or fast.

"The Longbottoms are young Aurors yet, but considering the fact that they're still alive, they're doing extremely well!" Moody barked.

Peter wasn't sure if this was supposed to be funny. Neither did anyone else, apparently; there were a few uncomfortable chuckles. The Longbottoms smiled wanly; Frank reached out and squeezed Alice's hand.

Moody scowled. "Oh, come on. Got to have a sense of humor in our line of work!

"Now, most of you are just out of Hogwarts, so you should know about the Patronus Charm, yes? Hands?"

Most of the Order raised their hands, including Peter: he had come across the spell in his Animagus research, but to James and Sirius, transforming themselves was much more impressive than just using any old charm, so they didn't bother learning it. Privately, Peter had tried it a few times, but he gave it up in embarrassment when he spectacularly failed to produce anything at all. "Good. Now, how many of you can perform it?"

Peter's eyes darted around the room. Of those assembled, only Lily and Remus raised their hands. A few of the older members nodded, including the Longbottoms. Moody shared a significant look with Dumbledore, who looked solemn. "Very well," Moody grunted. "Remus, is it? Remus Lupin? How about you give us a demonstration?"

Peter winced. Remus hated being put on the spot, and Moody's stare was unflinching. Remus looked around, head ducked, and pulled out his wand. His eyes squeezed shut tightly; it looked as though the concentration was almost paining him. Just when Peter was beginning to wonder if he was going to do anything at all, Remus' eyes snapped open and he pointed his wand at the empty carpet in front of him.

"Expecto Patronum!" His voice was uncharacteristically firm, and silvery smoke began to pour from his wand. Unsurprisingly, a wolf shaped itself from the mist. Peter did his best not to look around at the crowd's reaction. James, Sirius, and Peter had developed a knee-jerk defensiveness when it came to Moony's 'furry little problem', and it was hard to shake outside of the Hogwarts grounds. A sidelong look at the others told Peter they'd been thinking the same thing.

But Remus looked calm—Peter could even see a few traces of pride showing on Moony's pale face. The wolf was beautiful; Peter was a little embarrassed for thinking it, but it was true. It looked strong, and it shone like a silver sickle. He heard James' breath hitch beside him. "Merlin…"

After a few seconds, the wolf faded and Remus smiled a proud, private smile to himself.

Moody nodded sharply and clapped his hands together once. "Well done, Remus. Now, a Patronus is an immensely useful charm. It's tremendously powerful against lethifolds—nasty buggers, live in tropical places—and more importantly, their close cousins, dementors."

The grins that Remus's brilliant Patronus had inspired were dulled instantly. Lily looked down at her feet, and laced her fingers through James's.

"But why am I wasting time with this on the first meeting? I doubt any of you will be wandering around South America, and I certainly hope you don't end up in Azkaban. You've got more important things to do, right? Wrong." The sharp bark took Peter by surprise. "There's another trick to the Patronus Charm that's a real corker. A Patronus, you see, can communicate." He chuckled roughly as he looked around at the room full of puzzled expressions. "Truth to tell I had the same look on my face, and I thought I heard it all. But it's true. Dumbledore here, blasted fool that he is—" Dumbledore let out a soft tut as Moody laid a strong hand on his shoulder. "Discovered that a good strong Patronus can be used to carry personal messages across considerable distances. How about that?"

Sirius looked positively gleeful at the fact that Moody had just called Dumbledore a 'blasted fool' right to his face.

"As you might have guessed," Moody went on, walking back towards the front of the room. "Each Patronus takes a form unique to the caster—that is, if you get a good handle on it." He winked encouragingly at Remus. "To the average caster it's usually just an indistinct ball of light. Naturally, these forms make it easier to identify the witch or wizard sending the message. I should add that a Patronus can never be duplicated by another caster, although a person's Patronus can occasionally change form. However, this is rare, and typically occurs when a witch or wizard endures a massive emotional upset."

What on earth does that mean? Like a death? Peter had not seen this in his research. While it was pretty obvious that magic was affected by the caster's frame-of-mind (ask anyone who's ever been Splinched), it always seemed the strongest magic was the most temperamental.

"One of the best advantages that a Patronus offers is the ability to identify an ally. Through various sources—ahem—we've discovered that followers of Voldemort don't have the ability to produce a Patronus." Moody exchanged another look with Dumbledore. "There are some theories as to why that is—"

"Because they're a bunch of sadistic bastards?" Sirius hissed in Peter's ear. This was a bit rich, considering the stunts Sirius had pulled on certain students during school, but Peter smiled anyway.

Moody continued. "But I'm sure we can chalk it up to them having a bunch of charred, twisted bits of goose liver where their hearts should be."

Sirius laughed, looking pleasantly surprised, which earned him a wink from Moody.

"The key to a successful Patronus," Moody began, drawing his wand from an inner pocket of his thick black coat. "Is deceptively simple. A Patronus is the essence of goodness and of joy. Or hope."

There were a few smiles and suppressed snickers in the group, and Moody scowled. "Yeah, yeah. I know it sounds very airy-fairy, but if you want to fight the forces of evil, that's the best weapon in your arsenal. Anyway, the point is to call a happy memory to mind, to let it sort of fill you up." Moody glanced warningly around the room at any potential gigglers. "This memory will give shape and power to your Patronus. Not much is known about the ins and outs of all this, it's all beyond me, but we do know that a Patronus is made of a substance nearly identical to an extracted memory. If you've had the fortune to use a Pensieve, I think you'll know what I mean."

Peter hadn't even seen a Pensieve outside of his schoolbooks, although there were rumors that Headmaster Dumbledore had one. One of the wilder theories was that he used it to extract confessions from particularly difficult rule-breakers, but Peter knew from experience that was patently untrue.

"Does anyone know the other benefit of a Patronus?" Moody inquired, rolling his wand in his palms. It spat a few sparks into the air. No one answered.

"It's arguably the most important one—no offense to the good Headmaster."

Dumbledore inclined his head graciously from the carved wooden chair.

Moody's small black eyes narrowed. "Sometimes you see something ugly. Maybe you get called down to a crime scene to examine a body, or you watch a friend of yours get cursed to hell and back. Maybe you have to take down the statement of a brand new widow." He paused, as if remembering, and absentmindedly stroked a faint scar on his chin. When he spoke again, his voice was distant. "That stuff stays with you."

He cleared his throat and started to pace. "Some of you might think you're good in a crisis. You think that you've got the stomach for anything you might see out there…you couldn't be more wrong.

"It will affect you. And if it doesn't now, it'll catch up to you later. Always does. We are the only thing that stands between the ugly and the innocent. We take on that responsibility so others won't have to." His stare burned into each of theirs. "You'll find yourself in a lot of unpleasant situations because of it, and it's good to know you have a spell that'll calm you down and force you to remember the good things in your life."

The room was dead silent. After a moment, Dumbledore coughed softly.

The Auror's hard expression eased. "Er, and it works on those around you too; a good Patronus is better than the strongest Pepperup Potion you can brew."

Moody met James's hazel eyes. "By the leave of Mr. Potter, who owns this drawing room, I'd like you all to give it a go." James glanced around at the parlor and shrugged.

"I don't see why not. No harm in adding a few more memories to this place, eh?" He smiled wanly; Lily rubbed his shoulder.

So they did.