Chapter 4: An Afternoon Laced with Poison
The after-school quiet that settled over the campus felt like a lie after the midday bustle. Faint pink light slanted through the windows, casting long shadows along the hallway floors as the sun dipped toward the horizon.
That day, the biology club was organizing plant specimens in the science room, old pressed flower books, dried samples, and microscopes. As always, the club president Tashiro methodically worked through his tasks while the underclassmen silently followed their assigned duties.
But the quiet didn’t last.
“P-President! It’s Sudo-senpai!”
A female club member’s scream sent Tashiro leaping to his feet. In his line of sight, Sudo had stumbled out of the prep room, clutching his chest and doubling over. His face had gone pale, foam clung to the corners of his mouth.
“His hands and his fingers are twitching! What’s happening?!”
A teacher, alerted by the noise, rushed over and had Sudo transported immediately to the nurse’s office. The panic spread quickly throughout the school, and by the next day, the news had reached Ao and Hisui.
“I heard they found signs of a powerful neurotoxin,”
Ao whispered to Hisui during lunch. They sat in a quiet corner by the library window, exchanging notes.
“Which one?” Hisui asked.
“Strychnine. Even in tiny amounts, it causes violent muscle spasms. It can be absorbed through the skin or mucous membranes.”
“That’s not something you'd just leave lying around in a school lab.”
“Exactly. The question is: how did it get there? Apparently, the herb extract in the biology prep room had been switched and someone replaced it with a solution laced with strychnine.”
Hisui furrowed her brows and stared down at the table in thought.
“Strychnine comes from Strychnos nux-vomica ‘machin’ seeds. They're nearly impossible to obtain in Japan.”
“Right. They’re not even used in modern medicine. You need a special license to handle such hazardous substances.”
“Which means whoever brought it in is someone with rare access.”
The two exchanged looks.
That afternoon, Ao made his way to the biology prep room. The club advisor, Mr. Fuyukawa, had already left for the day, and no club members remained. The door was locked, but he happened to run into the school janitor, Kawazu, and borrowed the key under the pretense of retrieving a forgotten item.
As soon as Ao opened the door, a dry, herb-like scent hit his nose. Slowly, he stepped into the room, eyes scanning the rows of shelves lined with glass bottles.
Among them was a small vial with a handwritten label: “In Extraction.”
Wearing gloves, Ao lifted the bottle and held it to the light.
The sediment color was wrong.
The other vials held a pale green liquid but this one had a faint yellow tint.
He gently returned the bottle to its place and opened the logbook that recorded who had used what and when. But on the day of the incident, the entry was marked: “Forgot to record.”
Deliberate.
As he exited the room, he heard footsteps behind him. Turning, he saw Hisui standing there.
“Don’t scare me like that…”
“Sorry. You were investigating, weren’t you? I heard about the symptoms from the nurse.”
“It was strychnine?”
Hisui nodded.
“But here’s the strange part: strychnine normally causes severe seizures even in minute amounts, but Sudo’s symptoms were relatively mild. That means someone might have deliberately adjusted the dose.”
“A test run?”
“No. A warning.”
Ao straightened up.
“Revenge, a message, or… self-expression.”
“Exactly. Since I came to this school, I’ve had the feeling that someone’s been ‘testing’ me. Like they’re deliberately doing this where I’ll notice. But… who?”
Ao recalled a rumor about Mr. Fuyukawa, the biology club advisor who once mishandled chemicals and caused a student to suffer minor injuries.
Moreover, in the court records of Hisui’s mother’s case, there was a name listed as a former research associate:
Hiroyuki Fuyukawa.
“No way…”
“Is there a connection?”
“Fuyukawa may have studied the same medicinal herbs as your mother. There’s no proof, but… he’s suspicious.”
The next day, they posed as cleaning staff to sneak a look at Fuyukawa’s desk in the faculty room.
Inside a brown envelope buried beneath paperwork, they found photos of specimens including dried machine seeds.
The bizarre, spiky seeds were sealed in a labeled transparent bag.
With trembling fingers, Ao picked up the bag.
“These were… used in the incident?”
“Most likely. But we still don’t have enough proof.”
“Then we’ll run a chemical test. I’ll extract a sample and use a toxin detection kit.”
“…You’re serious.”
“There’s no turning back now. This isn’t just someone testing with poison. The next time… they might intend to kill.”
That night, they sat in the back of the same old café by the station, tucked into a quiet corner. Ao opened his laptop and prepared a self-made chemical analysis sheet. He added a small sample from the seed to a test solution with a dropper.
The result came back positive.
“There’s a reaction. Strychnine confirmed.”
Hisui closed her eyes.
“This makes it almost certain he’s involved.”
“But it’s still not decisive. The police won’t act based on just our findings.”
“Then we have to find another piece of evidence.”
Just then, a faint tap sounded against the window. They both looked up to see a shadow pass by outside.
“…Were we being watched?”
Ao rushed to the window, but no one was there.
That night, Hisui had a dream.
In a rain-soaked memory, she stood in her mother’s clinic. A man quietly stood nearby, and when he turned to look at her
His face resembles Fuyukawa.
