Hermione led us to the Hospital Wing but she did not remain with us. It was very dour place compared to other rooms in the castle. Frankly it put me in mind of the war hospitals I'd visited during my time in Afghanistan.

Olivia Flint lay on a bed in the far corner, presided over by a stern, elderly woman. She was conscious but grimacing in pain. The elderly woman gave us a withering glare as we approached.

"I'm a doctor," I explained. "Erm, a Muggle doctor, that is."

Her withering glare somehow turned even more withering.

"And I," she said, "am Madame Pomfrey. I have been the matron of Hogwarts' Hospital Wing for over half a century, and I do not require anyone's assistance."

"I didn't mean to imply that you did," I hastily replied. "I just — well, I saw that when she was injured someone was lifting her neck —"

"Yes, yes, I know. Fools damaged her cervical spine at the C2 and C3 vertebrae."

"Severing the spinal cord's connection to the brain could result in paralysis."

"What!?" Flint cried out in alarm, eyes going wide.

"Nonsense," Madame Pomfrey said. "Muggles and their archaic medicines. She produced a vial from her rolling cart. "All she needs is a bit of rest and some Skele-Gro."

"But wait — he's right! I — I can't feel my legs!" Flint said.

Madame Pomfrey shook her head, and shot me another venomous look. "See what you've done? You're distressing my patient!" She turned back to Olivia and administered her medicine. "Skele-Gro can be painful; I'm giving you a sedative so you can sleep away the worst of it. Yes… there you go… You'll be back on your feet in a couple days. Your legs will be perfectly fine."

Madame Pomfrey sealed the vial of Skele-Gro and strode off, muttering under her breath something about "Muggle doctors." As Olivia's conscious receded, her eyes rolled back. She pointed at me, beckoning me closer. Her hand reached out feebly, trying to pull me in. I stepped forward.

"Yes, Olivia?"

Her eyes rolled back. She spoke in a strained whisper. "Tried… tried to kill me…"

"Who?" I asked. "Who tried to kill you?"

But Flint gave no reply. Her eyelids fell shut.

Moments later, Madame Pomfrey returned, and Flint's Quidditch teammates arrived — all of them except Malfoy Jr. They rushed to her bedside, interrogating Madame Pomfrey about her prognosis.

"Oh, Olivia!" said a Slytherin beater. "Are you alright? Is she going to be alright?"

"She'll be fine," Madame Pomfrey said. "And no more than six visitors at a time!"

My presence made six, so I backed away, leaving Flint's teammates a chance to be with her. Sherlock apparently stood near the opposite bed, inspecting another patient's chart. I related to him what Flint had said, which I thought was quite suspicious, though Sherlock seemed only marginally intrigued. He seemed more interested in this other patient, who lay supine upon her bed, pale and seemingly unconscious.

"Zoe Lestrange. Fifth year Slytherin. Committed to the Hospital Wing three days ago, the same day Dexter Zabini died."

"Hmm… well that is—"

"—confidential information!" snarled Madame Pomfrey. Despite being frail and elderly, she was evidently stealthy as a cat. She snatched the patient's chart from my hands.

"It may be relevant to the case I'm here to investigate," Sherlock said. "What can you tell me about this patient? What time of day was she admitted?"

Madame Pomfrey seemed poised to argue, but ultimately relented. "She… it was during the daytime. Early afternoon. She was found in her Common Room, comatose. She hasn't been responding to treatment."

"Comatose? Why? What happened to her?"

"She was poisoned."

We had a couple hours to spare before our appointment with Fiona Clearwater. I had suggested we occupy the time by meeting with another of Dexter's Professors, or perhaps one of Dexter's fellow N.E.W.T. Herbology students. While Hermione believed only a Professor would have the ability to bypass the Greenhouse's arcane lock, students who had the key were also people of interest.

Sherlock had agreed with my proposal… until his attention became engrossed by a statue of a one-eyed witch on a third floor corridor. He was convinced something about it was different.

"Different how?" I asked.

Sherlock pursed his lips, squinting at it. Considering the statue from different angles. "It has shifted, ever so slightly, since we passed it this morning. It's not right."

I shrugged. "There are flying broomsticks, talking paintings, incorporeal ghosts… but you draw the line of credulity at a statue that has 'shifted'?"

"Incorporeal is the normal variety of ghost," Sherlock said, his analysis of the statue not wavering. He began circling it, poking its one eye.

"There is no normal variety of ghost. Everything about this place is … its madness." I shook my head.

Sherlock did not reply. Frankly I don't think he even heard me.

"What do you make of Flint's last words?" I said after some time, trying to break his reverie and return his focus to the matter at hand. " 'Tried to kill me'?"

"What? Oh. Well her own teammate had just walloped her with a bludger, she fell and nearly died. Seems quite open and shut. But this fascinating statue — "

"—is quite irrelevant. What about Zoe Lestrange? Poisoned the same day Dexter is killed. Mighty odd coincidence, is it not? Conforms to one of your seven preliminary theories—"

"Eight. Actually six now, I had to scratch two off on account of exculpatory evidence. I'm getting hungry. Are you hungry? Is it time to meet Fiona?"

We had a quick bite of dinner and then afterward met Fiona in the Entrance Hall. She led us to an empty classroom on the second floor. The desks had been swept aside to either side of the classroom, and a raised dais — possibly a dueling stage — was situated in the center of it. As soon as we entered the room Fiona seemed to tense up.

"Do you hear that?" she said, in a hushed conspiratorial whisper, holding an arm out as though to prevent us from tripping some invisible trap.

"Hear what?" I asked. The silence in the room was almost deafening.

"Tarsnips," she said.

"Tarsnips?"

"Multitudes of them. Flitting around on their cherry-hued wings. Invisible, of course, which is why you don't see them. They feast on your Chi energy, but as long as we don't stay here long we'll be safe."

Sherlock shook his head at me, mouthing the word "moron." I wasn't sure I shared his skepticism. The existence of magic had so dramatically expanded the scope of what I thought was possible in this world that… well, why not Tarsnips? There seemed room for any possibility, even the Snargleworts allegedly plotting mankind's downfall.

"Right," I said to Fiona. "So, you're a Slytherin Prefect."

Fiona's attention still seemed captivated by the imaginary tarsnips that were supposedly frolicking about the classroom.

"Wha—? Oh, yes, I am."

"And did you work closely with Dexter Zabini in that capacity?"

Reluctantly, ever so reluctantly, Fiona peeled her gaze away from the invisible tarsnips and turned to us. She plunked down in a nearby seat.

"Not really," she said a bit airily, as though her attention was still elsewhere. "We were both Slytherin prefects, but we didn't work together or coordinate. Prefects don't really do that."

"But you knew him on a personal level, right?"

Fiona shrugged. "He was my lab mate in Defense Against the Dark Arts. Sometimes we compared notes for Transfiguration — he was very good at Transfiguration. He was smart and kind. Not like the other Slytherin boys…"

"I see. Was anyone close with him? Did he have any friends?"

"Just a few I think. He was introverted. Like me actually. Sometimes he would go down to Hogsmeade with Tristan Macmillan and Sean Montague… Oh, he had a girlfriend too. A fifth year Gryffindor girl. Yolanda, I think her name was."

"Was there anyone he didn't get along with?" Sherlock asked. "Rivals, enemies?"

"Slytherins," she said without hesitation. "Most Slytherins didn't like him."

"Because he was a Prefect."

"And because his girlfriend was a Gryffindor, and because he was intelligent and successful and handsome and well-liked by the teachers." Fiona shrugged and gave a sad sigh. "Slytherins are cunning and ambitious but they can be quite jealous and vindictive as well."

"Did anyone seem particularly jealous and vindictive of Dexter? Anyone whose envy or resentment might have boiled to passionate contempt?"

"Scorpius," Fiona said without hesitation. "Scorpius and Dexter got on like cats and dogs, as my father would say."

"We've surmised as much. Anyone else?"

Fiona rubbed her chin, considering. "Arjun Patil. The Head Boy."

"The Head Boy?" I asked.

"The Head Boy and Head Girl are 7th year students who lead the Prefects. Arjun and Dexter used to get on like old mates. Then this year after Arjun became Head Boy…" she shrugged. "I don't know what happened. But I know Dexter didn't take well to orders Arjun gave him."

"What sort of orders?" I pressed.

"Well… normally us prefects are supposed to stick to our patrols. You know, monitor this floor or that floor after curfew. Well, recently Dexter kept wandering off. Arjun and him had a row about it. I heard them one time going at it after Transfiguration."

"Wandering off to go where?"

"Someplace on the third floor. There's a wing on the third floor that's off limits. I don't know why Dexter kept returning there. I think he was investigating something. And that night… the night he died… I saw him leave the Slytherin Common Room. I figured he was going there… to the third floor. Next day I heard they found him dead in the Greenhouse."

"That last time you saw him in the Slytherin Common Room," I asked, "what was he like? What was his mood?"

Fiona shrugged. "Dexter only has one mood. Calm, quiet, confident. You never see him crack a smile or show emotion. He's very stoic."

"Scorpius — was he there that night?" Sherlock asked.

"Oh yes, he was there. Seemed nervous and fidgety. Saw him staring at his homework, I remember. A blank piece of parchment. The weird thing is he didn't have any textbooks, and he wasn't holding a quill. He was just staring at this blank piece of parchment, occasionally glancing around the Common Room. After a while he left."

"Who left first? Scorpius or Dexter?"

"Dexter. Then five minutes later Scorpius followed. It was him, wasn't it? Scorpius followed Dexter and killed him?"

Sherlock didn't answer, but he didn't need to. Indeed, the evidence seemed to be stacked against the junior Malfoy.