September, 1992. Hogwarts. The incoming class of children have been Sorted, and all the students and staff are settling in to partake of the delicious feast. First-years are getting to know their new housemates; old friends are sharing news of the summer. At the high table where the faculty dine, there is (as there so often is) a new colleague to meet.

Minerva has gotten a seat next to said new colleague, by the power of seniority and gravitas. Filius is on his other side, by the power of being too short to hear the conversation if he isn't. Pomona is on Filius' other side and enthusiastically leaning around him asking, "So you're from across the pond, then?"

"Yes, ma'am. Department of Magical Law Enforcement, California division. And a diehard Los Angeles Lizardfolk fan as well, dunno if you do much Quidditch around here."

"We do indeed. I'm afraid I don't follow the American leagues, but there's a thriving British Isles league, and of course you can watch the next generation of players right here at Hogwarts."

"I'll plan to do that! That's great. The Houses sort of split kids into teams already, don't they? And that Sorting was something else. I tell you, if we had a Hat in the department that could look inside people's heads, maybe my job would be a whole lot easier. But what do I know. Say, what's this food?"

"Treacle tart!" chirps Flitwick, "And if you haven't had it before, I highly recommend it."

"Thank you." Columbo chews the treacle tart thoughtfully.

"Where's it all come from? So many different dishes, it must take a whole lot of work."

"We have the largest staff of house elves of anywhere in Britain, and they do an excellent job."

"Oh, I see. Is that a fact? I've never met a house elf before—we don't really see a lot of them in L.A. Same as with ghosts, in a way. I mean, occasionally you'll get a haunted hotel room, we had a ghost stampede at La Brea a few years back, that kind of thing, but nothing like this." He sweeps his arm in the general direction of the ghosts throughout the hall.

"You can really tell you're in a place with a long history. I was just reading about the Hogwarts ghosts on the train. It must be amazing to live here all the time, huh?"

"It really is." It's hard to remember that, sometimes, but never at the start of the year. Not when she gets to lead the first-years into the Great Hall and watch the same awe spread across every face, the purebloods who grew up in mansions and the muggleborns who learned about magic a few weeks or months ago.

Flitwick smiles too. It's a great place and he's glad the American appreciates it properly. "I quite enjoy it. Is this your first teaching post, then, or have you taught before?"

"Me? Oh no, not really. Coupla lectures here and there, never full time. No, this is a brand-new opportunity. Turns out Professor Dumbledore pulled some strings with my boss's boss, and here I am—teaching in a thousand year old castle! Would you believe it? I wonder how they do that enchantment with the ceiling. Very atmospheric. I just bet it says something about that in my book. So what do you teach, sir?"

"I teach Charms," says Flitwick, "which makes me just the man to ask about the ceiling!" And he's grabbing the portkey to infodump town for as long as Columbo cares to indulge him. With some help from Pomona, as it transpires that the Great Hall ceiling is composed partially of living, magically camouflaged skyvines.

Columbo has inexhaustible interest in this frankly breathtaking feat of magical architecture! And Pamona and Filius make excellent dinner companions; Filius is sharp as shears, and Pomona has a completely unpretentious way of knowing seemingly everything there is to know about Herbology. It's going to be an interesting year, he thinks.

Eventually the bottoms of serving-dishes and the tops of plates become visible, and the students are led up to their dorms, and the faculty retire to the apartments near their respective classrooms. 

And in the morning, there are classes. Starting with, thanks to the inscrutable whims of the schedule, the second year Gryffindors.

This one is looking at him with an expression Professor Columbo may find familiar, if he's ever done his job in a room with a mirror.

Oh, that scar. Through practiced stoicism, Columbo manages not to let on. Kid probably gets enough attention as it is. But he files away that scar, and that look, and he glances around the whole classroom of second-years, and finds the beginning.

"G'morning class. I'm Professor Columbo, and this is Defense Against the Dark Arts.

"Defense is, famously, a very big subject: it's not about a particular kind of magic, like Transfiguration is about changing substance, or Magical Creatures is about animals, or Potions is about putting natural magic in bottles. Oh sure, you've got to know a little bit of all of these, that's the foundation of Defense—and I will be talking with you and your other professors about what you can already do, so we can build on that— but Defense isn't any one type of magic.

Defense is a way of thinking. Using your brain, and what you know, and what you've practiced, to deal with magic that can hurt. Dark Arts: magic that can hurt. In this class, you're going to learn how to do that. Or I oughta say you're going to bring your ability to another level; I know I'm still learning more about Defense, all these years later. You've got to know your stuff, first of all. We'll be learning a bit about curses, and poisons, and Dark creatures. And then—I'm a very practical person— you've got to be able to recognize what you're dealing with. Outside of a classroom, no one's going to say 'Hey, I'm about to turn your legs into jelly', and no one's going to label the hinkypunks from the will-o-wisps. You've got to be able to recognize what you know in an ambiguous situation."

He pauses thoughtfully. "Let me give you an example. Suppose you've just seen someone—your grandmother, maybe, a very nice lady, you love her to pieces—curse your neighbor's tree, and the next day the tree dies. It sure looked like her, in her usual purple shawl, but you're pretty sure your grandmother would never do that kind of thing, or never willingly. It's a very strange situation. An ambiguous situation. Now I want to hear your ideas. What Dark magic do you know about that could explain this? Maybe it's Dark magic, maybe it's a misunderstanding or a deception or coersion, anything that could make it look to you like your grandmother just decided one day to curse a tree, when really that's not true, or not the whole story. What do you think?"

The girl who looks like she got her initial rations of hair and teeth and immediately got back in line for seconds gleefully puts her hand up. Everyone else seems to consider this a sufficient collective response.

"Yes, ma'am!"

"It could be someone who took Polyjuice potion to look like my grandmother, or just disguised themselves as her with clothes and makeup. Or Transfigured themselves, but that would be dangerous. Or she was threatened into doing it. Or she thought she saw a dangerous creature hiding in the tree."

"Terrific thinking, Miss—?"

"Granger. Hermione Granger. Thank you, Professor."

"Miss Granger is showing us how to juggle different theories at once:

What if it was somebody else? Maybe it was Polyjuice potion, great answer: a sophisticated potion that makes you look like somebody else for about an hour. Self-transfiguration, very dangerous like you said, I don't recommend it, desperate people sometimes do it, very possible also. I especially like that Miss Granger included disguises: magic folk sometimes forget about disguises, which you can do without magic and which leave no magical trace behind.

Or What if my grandmother was forced? Threats are one way to do that, yes, and perhaps you've heard of Dark magic that can do that, too.

What if we assumed the wrong motive? Very important! In day to day life, answers seem obvious. You observe, you conclude, and there's no gap between what you're seeing and what you're concluding. What if my grandmother wasn't trying to damage the tree, but swatting a dangerous creature. It's a very important defensive skill, to separate what you observe from what you assume. You need it in all kinds of Defense work, whether you're a curse-breaker, a detective, or a duelist. We'll practice that also.

Here, we're seeing how to juggle several different ideas that may not all fit together, without getting stuck on any particular one. The point is to question as much as possible, to make as many as we can think of. Anyone else think of more we can add? Other motives? Any magical forms of coercion? What about magic that could be targeting me in this situation?"

Granger puts her hand up again!

And so does a round-faced nervous-looking boy, very tentatively.

"Yes sir! Mr.—?"

"The—I'm Neville Longbottom—the Crabbenwalter's Regenerating Hawthorn produces better fruit if it's hit with a Withering Hex at the start of flowering season. But that only makes sense if it's March so that's probably not it sorry."

"My goodness. Blossom thinning, you know I never would've thought of that? That's a very smart idea. I'll tell you why. Whenever you're sizing up a situation, what's really gonna help you is the specifics—the time of year, the species of plant, and all the little tidbits about how the world works. You see those specifics, Mr. Longbottom. Details matter. I'm not a gardener; you clearly know your stuff; in a real life situation I might've gone on thinking my grandmother had actually hurt that tree, unless I had someone like you, or someone like Professor Sprout, to explain it to me. Yes, a very smart idea. It also goes to show you that the Dark Arts are about use. Now don't get me wrong! There are some spells out there that a person should never use! But see, a Withering Hex is not just for hurting people; it can make your hawthorn tree stronger. And Exigent Exsanguination can be used to kill, but I've seen it save a life of a poisoning victim. Even Dark creatures are very dangerous, we've got to respect them and keep our distance, but they aren't evil. It was springtime, and your grandmother was helping the tree to bloom."

"Alright. Flexible thinking. Question your assumptions. Juggle your theories. Look for other ideas. Use specifics. Are we getting a feel for it now? Any other suggestions?"

Seamus Finnegan raises his hand, introduces himself, and says, a bit stubbornly, "You could just be wrong about what your gran wouldn't do. People are wrong about each other sometimes."

"Oh, yes. Mr. Finnegan is raising a very good point, no doubt about it. People are complicated. They'll surprise you with what they can do, both good and bad. Even your sweet little grandmother—heh, of course I don't mean your grandmother in particular, just speaking very generally— maybe she's not so sweet after all, or maybe someone put her up to it, maybe she's having a bad day. It could be a lot of things. And sometimes you can even reason out why. The point is, we shouldn't let our assumptions and our loyalties keep our minds closed. I don't mean be paranoid! Me, in my line of work, people ask if it makes me paranoid. I like my job. Oh, I like it a lot. And I’m not wound up by it. And I don’t think the world is full of criminals, and full of murderers. Because it isn’t. It’s full of nice people just like you. And if it wasn’t for my job, I wouldn’t be getting to meet you like this. What I'm saying is, Defense Against the Dark Arts often comes down to, not who's the strongest spellcaster, or who got the best grades in school, or the rarest ingredients. Often it comes down to these fundamental skills: can you challenge your basic assumptions? Can you access what you know instinctively? Have you practiced how to respond, over and over? And can you think critically, and can you use your imagination? All of you here today have powerful imaginations, there's no doubt about that either. We're going to learn how to use that imagination, that critical thinking, to find out what motivated your grandmother to hex that tree. We're going to develop these practices, which will make you better at magic, and better able to protect yourself and the people around you from harm."

Whatever else he may be, this professor seems like he intends to teach something, so that's good. Hopefully he doesn't assign too much homework about it.

In no time at all, it seems, Columbo is wrapping up the first Defense lecture of the schoolyear. It's great working with these kids, a real smart bunch.

"... and the nephew had charmed his pest-control box to be a Portkey, so when the boggart climbed in— poof, there went the murder weapon! So the reason we couldn't find a gentleman matching that description, the reason the desk didn't have any axe marks in it, is because he was completely made up! Nothing more than a frightening rumor for the specific purpose of shaping a boggart when she was home alone. Just goes to show you, if you're banging your head against the wall trying to figure out how, you can always try falling back to why— to motive. And, maybe don't put your nephew in charge of pest control, I suppose. Alright, that's the end of the story for today. You all are dismissed; I'll see you next time."

Over the resulting din of shuffling chairs and bags, Columbo suddenly shouts, "Oh wait, I forgot. Uh, just one more thing before you go, it'll only take a moment. For next class, please complete the table of jinxes and hexes from the blackboard. Think creatively— remember illusion magic. You can work together, that's fine, put your heads together, but make sure I can tell which parts were yours. Sign your name by them if you have to. Alright, that's really it. Goodbye!"

Huh, a group project. Hermione still thinks of that as a muggle school thing. It's been a while since she's had to choose between Following The Instructions (doing part of it and letting other people do part of it) and Getting The Right Answer (doing it all herself).But then she realizes that she can just do the whole assignment herself, then help/harangue the other students into doing their parts, and then turn in both copies.

"Welcome, Lieutenant," says Professor Trelawney ethereally. "What brings you to my distant abode? Ah, no, you needn't tell me—you're looking for a book. I have several reference volumes you'd be welcome to borrow."

"Thank you, ma'am, that's very kind of you, I'll keep that in mind. No, this is just an old habit of mine. I like to take a look around, get to know everyone, hopefully learn the ropes, since I'm new here and all. Hadn't gotten a chance to chat at the staff table, they told me you're often up here. Have you eaten?" Columbo hoists a rumpled paper bag. "Made a few sandwiches, plenty to share. That is, if you aren't very busy right now."

"Not at all, my schedule is quite light. Even among witches and wizards, only a few truly have the Gift of seeing what is hidden. I would be happy to dine with you."

"Oh, terrific. Gee, the gift of seeing. You know Hogwarts food is very impressive? I must've tried five or six things already I never had before in my life! What an experience. But sometimes it's nice to have a sandwich. A simple sandwich. Oh, here you go, yeah, take whichever you want. So I was checking out the Hogwarts kitchens. Boy, I tell you, those house elves run a tight ship. Very gracious, incredibly efficient, eager to please. I've never seen spellwork like that before either. Did you know they can apparate anywhere in the castle? And here I am marching up and down these stairs all day, yeesh. To tell you the truth, I think I upset them a bit when I said I wanted to make my own sandwiches. Seemed to take that as an insult. I didn't mean anything by it, that's just what I'm used to. I like to do it myself. So, when you say gift, what kind of gift are we talking about? Astrology or something?"

Professor Trelawney needs to do more exercise to get food than anyone in the castle except Professor Sinistra, and the latter is far less inhibited about ordering room service. A sandwich starts disappearing with ruthless efficiency. 

"Astrology is one of the many methods by which the future may be divined by those with the talent to do so. I am also experienced with palmistry, tea-leaf reading, tarot, and the art of making and using crystal balls. But in truth, the future is sufficiently connected to the past that it may, with sufficient skill, be discerned from almost anything. You are from the southwestern portion of the States, are you not? Have you ever met a fire-reader? It is not my preferred process, but experts can attain remarkable results."

"No, uh. I find I'm interested, hearing you talk about it now, and seeing this very beautiful room, but I'm clueless in that department. I don't even know what those colorful things you've got dangling over there are for. You mean to tell me a person can look at a fire and see what's going to happen in the future?"

"A fire, or the night sky, or tea leaves, or at times the inside of her own mind."

"Sounds like a thrilling kind of life, figuring out the future and all, no matter what tools you're using. Maybe a lot of pressure, too. Do you like what you do? I mean, does it get to you?"

Trelawney's giant eyes turn away from Columbo to look at the floor for a moment. "I'm afraid it does, at times. So many futures are not what one hopes . . . even yours. I see your future descending into darkness . . ." She inhales sharply and makes unblinking eye contact again. "Still, better to know."

"You know, I agree with you? I'd rather know, too, if I could. In my line, I'm always trying to figure out what happened in the past. Same idea, though. Really it's the same thing. Say, maybe I should stop by from time to time, you could show me how it works. Fortune telling, I mean. Tea leaves, cards, palm-reading, whatever. I find it all very interesting, like I said, and it sounds like you know a lot about it. I'd bring along some more sandwiches, or maybe teacakes. Wish I had brought some with me today, come to think of it. We could have tea. Do you have tea? I didn't bring anything to drink."

"I am always happy to teach, though if you lack the gift of Sight I may not be able to do as much for you as you would hope. But company and sandwiches are always welcome, and I can always put on a pot of tea."

Not long thereafter, Harry Potter has detention for grand theft auto. It's not totally clear why it's Professor Columbo's job to proctor this detention, but it isn't totally clear who else ought to do it, given that the majority of the infraction happened off school grounds before the start of the school year. Anyway, here he is.

"Mr. Potter! How ya doing, son? Come in. Just the guy I wanted to see. Well, I know this is detention, nothing we can do about that, but I've kinda got myself into a mess and I could really use an extra set of hands.

See I was walking down to Hogsmeade this afternoon and found this little fella nosing around in the grass. No idea what he's doing there, no collar or anything, really needs a bath. So my question for you is, you ever wash a dog before?"

A bleary-eyed basset hound is slumped comfortably on the floor like a pile of laundry.

So is it Columbo's dog now? Whatever, at least he's not going in the Forbidden Forest again.

"I've washed cars?"

"Good, same principle. For dogs like this, you just gotta keep the inside of the ears dry and make sure you get into all the little wrinkles. You can use magic, or not, as long as you're gentle. My father, smart man, very kind man, not a drop of magic, he's the one that taught me when I was a kid. So that cauldron has water ready to go, not too hot, and this blow-up pool is for the dog to stand in. All we gotta do is get the dog into it. You willing to cooperate, dog?"

The dog gives a doleful sigh.

"I don't know what I'm gonna do with this guy. First he follows me to Hogsmeade and back even when I tell him go home, dog! Now he won't budge. Alright, so you fill up the pool with some water and I'll lift him in. Motor vehicles, huh? You do a lot of work without magic growing up?"

Harry starts transferring water to the pool and shrugs. "Chores and stuff."

"Oh, uh-huh. Huuup, into the water with you! G'boy. No, stay there, oh very friendly. Hang on, I gotcha, I gotcha, yes. Alright, here, pour a little water over his back and we can start wetting the fur. So this buddy of mine from work, family never heard of magic, he did a lot of chores by hand growing up, too. Terrific detective, by the way, real hilarious guy, lotta stories to tell. I mean, this guy'll put you in stitches. This one time, as a little kid, he was at the grocery store, and he wanted ice cream so bad but his parents wouldn't let him. And he starts throwing a fit and then they turn around and what do they see? Every tub of ice cream in the place bouncing and hopping after their cart in a neat, single file line! Can you believe that! Like little ducklings! Had to rope off the whole building til they sorted it out. I told him, hey don't let it get that far while I'm around, okay, if you want ice cream, I'll spot you the sickle. "

That gets a wry chuckle. "I hope he didn't get in too much trouble." Pouring water on the dog. Trying to block the dog's attempt to get out of the tub, with mixed success.

"Not too bad. Onset magic, you know, these things happen. Bet you had a few incidents yourself. So once they're soaked through like this, we just grab our shampoo and our brush and—oof!" In a cascade of bathwater, the dog makes a spirited lunge for freedom. "Nah, c'mere dog! Sorry about this; he's got no sense of personal accountability. None whatsoever. We might get pretty wet—why don't you grab those enchanted towels just in case? Then I'll try to hold him still, and you brush."