Sejeong and I walked into poisons class and take a seat at our table. It feels like a medieval version of the chemistry lab back in Jeongseon. There are two students to a table with various metal instruments and glass jars. Only, instead of individual Bunsen burners, there is a fireplace used to heat things, and there are no safety glasses or plastic gloves to protect us. Sejeong says everyone learns the hard way what not to touch, which means I'm not touching anything I don't absolutely have to.

We're now in our second class of the day and there hasn't been a word about the guard's murder. No one's questioned us or announced that there will be an investigation. It's obvious the other students are on edge, too. Except for Rosé, who, as far as I can tell, seems to find everyone else's discomfort amusing.

Taemin stops in front of our table and picks up a glass vial of god knows what. He twirls it and studies the liquid inside like it's captured his complete interest. "Two murders since you've arrived, Suzy - and I hear one was right outside your dorm. Yet you're sitting here, while Jennie is in the dungeon." He looks over at me and I can see the threat in his eyes. He was close with Kai, but it's clear that what happened with Jennie is a much bigger deal to him and he'll make me suffer for it if he can. "But I'm sure that will be corrected soon enough." He drops the vial carelessly on the table, sending it rolling along the wood, and goes to take his seat.

Sejeong grabs the vial before it crashes to the floor, and by the look on her face, I know whatever is in it is definitely something toxic.

"Sit, my lilies," says Professor Hisakawa.

Hisakawa . . . Origin from Japan and can be broken down into two parts, hisa, meaning "a long time ago," and kawa, meaning "stream" or "river." I was intrigued by the name as a child because of one translation I found that listed the meaning as "river of forever."

Hisakawa stands in front of the fireplace humming while everyone settles. She's a beautiful, thin woman with curled bangs and hair that reaches all the way to her waist. "We often talk about poisons in terms of their specific formulas and intentional implementation, but today I would like to discuss poisons a little differently. You all know King George the Third, who was born in 1738 and held the British throne through the American Revolution? Well, it's been proposed that he had a genetic condition that caused him to suffer periodic attacks that the royal physicians at the time were treating with tartar emetic - an antimony-based medicine used to induce vomiting. Antimony is frequently found in nature with arsenic . . . and often contaminated with it." She pauses. "Ahh, I can see the lights turning on in those brains of yours. In the 1960s there was an analysis of King George's hair and it was found that arsenic concentration was seventeen times the lethal limit."

"The physicians' notes described both forcing the king and deceiving the king to take this poisonous medication. Wickedly fascinating, isn't it? Now, his medical condition at the time disrupted heme synthesis. And what does arsenic do?" She rolls up on her toes and back down again. "It also disrupts heme synthesis, making his condition worse and ultimately making the kind more dependent on the royal physicians who were poisoning him." She looks at all of us to make sure she has our attention. "Now, this is a curious situation because what outwardly appeared to be a caregiving tactic was slowly killing the king. And with the effect of the poison mimicking his preexisting condition, some might say it was a perfect crime."

Hisakawa smiles. "This is an example of a larger idea I want you all to think about. But let's talk about arsenic for a moment. It was wildly popular in the Middle Ages; everyone fell in love with the agony and romance of it all. Who knows why?"

I've never seen anyone so delighted by poison before and I really don't know what to make of it.

"The Borgias were the stars of arsenic poisoning," Rosé says from her seat next to Jimin. "It's said that arsenic improves the taste of wine, and the Borgias hosted a great number of dinner parties. Lucia Borgia carried the poison around in a secret compartment in her ring."

"Oh yes, the wine bit is one of my favorites," says Hisakawa. "And I've always like that Lucia. What a name. Anyone else?"

"Arsenic was widely available in the Victorian era and was even sold in grocery stores. Woman used to eat it or mix it with vinegar or chalk and rub it on their forehead because they thought it would improve their complexions and reduce wrinkles," Jimin says, and I notice he has a cut on his hand that wasn't there yesterday in fencing when Jennie attacked me.

"Absolutely. Arsenic has been used for any number of things - in cosmetics, to preserve food, as a pesticide, to dye fabric. Still, there's something specific I'm thinking of," Hisakawa says.

"Arsenic poisoning resembles cholera," Sejeong says. "Often times people would be pronounced dead of natural causes."

"Ding ding ding!" Hisakawa exclaims, and Rose rolls her eyes, clearly annoyed that Sejeong got the right answer. "A poison is truly great when it leaves no evidence behind, when its effects pass for an illness or when it's already present in someone's life and you only need encourage the interaction with it." She looks around the room. "The sixteenth-century philosopher and toxicologist Paracelsus famously said: 'All things are poison, and nothing is without poison. Only the dose permits something not to be poisonous.' What we learn from that profound statement is that there's poison in every environment. While something can be helpful in a small dose, it can be lethal in a large one. I'm not only talking about substances here - medications someone might be taking or cleaning products they use. I'm asking you to look beyond what is obvious to the more subtle and, if you can master them, the best of the poisons: emotional and psychological. If you can dose someone strongly enough with either one, death is likely to follow with no physical evidence left behind. The tactics with these are hard to detect, and it's only in the subtle changes that any real pattern can be discerned."

I'm not sure if that's the most disturbing thing I've ever heard or if she's merely shining a light on something important. People can drown in sorrow, kill a friend in mistaken rage, and isolate themselves out of paranoia. But if someone is purposefully pulling those strings, would you detect it if you were on the receiving end? Again I have this nagging feeling that I'm hearing more than just lessons. Not to mention that appa used to say something similar about detecting patterns. It feels like every time I turn around I'm realizing how little I understood about my life in Jeongseon.

The smell of pancakes and warm blueberries wafts into my room and I practically fall out of bed as I run for the kitchen. I wrap my arms around Appa's back as he mans the frying pan.

"Happy seventeeth, Suzy," he says, and turns around to give me a big hug and a kiss on the forehead. "Uncle Jin's already called . . . twice. Even though I told him you were still sleeping." He smiles and shakes his head. "He'll be here by the time you get home from school - with some ridiculous present, no doubt."

"Speaking of ridiculous presents," I say, and swipe my finger through the freshly whipped cream on the counter. "Where is it?"

"Where is what? he says, but by his tone I can tell he knows exactly what I'm talking about.

"The surprise you've been promising!"

"Oh, right," he chuckles. "I decided against it. I thought maybe you've gotten too old for presents."

I give him a hard look and he laughs. "No dad jokes right now. This is my birthday we're talking about."

"Well, I'm sure it's around here somewhere," he says with a mischievous smile.

I groan. "You hid it, didn't you?"

He shrugs.

"Okay, give me a hint," I say.

"Look for the subtle things that are different, a pattern. They'll point you in the right direction."

"Omo. What if I don't find it before I have to go to school. This is child abuse, you know," I pout.

He smiles and flips the pancake. "Well, I suggest you do find it, otherwise you won't have the keys to drive your new truck to school," he says, and my mouth drops open.

"My new what? My . . . No! Seriously? No!" I scream and jump up and down. "I have a truck? Is it black? Or silver? Or -" I run to the window, and sure enough there's an old silver Nissan forerunner in the driveway. "I will love you forever for this!"

How many of these moments were there, where Appa was teaching me something Strategia-esque and I thought nothing of it? What I really can't understand, though, is why he didn't tell me who I was all these years. And what the hell is going on with him and Uncle Jin right now that would have him suddenly send me into this school?

He was right when he said I know things that will keep me safe, but if I can't identify them, they don't do me any good. If only I could talk to him, I think, and the thought makes my heart ache. I've never missed him and Jeongseon so much in my life.