The Groom's Murderous Motive
Seeing Ms. Matsumoto's condition, Conan rushed over to Ran and had her call a doctor and the police at once.
It was then that he noticed Xia Yu standing off to one side, completely still, and a flicker of confusion crossed his mind. But there was no time for that — saving Ms. Matsumoto came first.
Conan leaned in close to examine her. Little by little, his brow furrowed. Something was wrong. Ms. Matsumoto's condition was strange — she didn't seem to actually be hurt at all.
His gaze drifted to Xia Yu — the one who had stood apart from the very beginning, done nothing to help, and had even, ever so subtly, kept the other guests from approaching Ms. Matsumoto. She had probably let Conan get close precisely because he was a little kid, assuming he wouldn't be able to tell what her real condition was. (In truth, Conan had simply moved too fast for Xia Yu to stop him.) Realizing this had to be connected to her, Conan wondered what Xia Yu had said to Ms. Matsumoto to make the woman play along like this.
Still, Conan said nothing. He hadn't known Xia Yu for long, but he'd come to understand her personality well enough to know she wouldn't do something like this without a reason — especially not something that required convincing Ms. Matsumoto to cooperate. But what could that reason possibly be?
Then he recalled Xia Yu's reaction earlier. Could this have something to do with the groom?
The ambulance arrived quickly, and Conan watched as Ms. Matsumoto was carried out and rushed to the hospital.
Since most of the wedding guests were police officers, the scene was secured almost immediately, with Inspector Megure himself taking charge.
The forensics team confirmed it: the substance mixed into the spilled lemon tea was sodium hydroxide.
"Sodium hydroxide?" Xia Yu blurted out in genuine surprise.
She had assumed that anyone who would choose to drug the bride at her own wedding — to end a woman's life at the moment of her greatest happiness — must have carried tremendous malice toward her, and would surely have chosen a lethal poison. She had never imagined the groom would use sodium hydroxide, a substance that wasn't deadly at all.
To be fair, sodium hydroxide was a powerful alkali, intensely irritating and corrosive. Ingesting it could permanently burn the digestive tract, and in severe cases even cause shock.
But that same intense irritation was exactly the problem — or rather, the safeguard. Anyone who accidentally swallowed it would notice immediately and spit it out, never consuming enough to go into shock.
In other words, the groom had never truly intended to kill Ms. Matsumoto.
But that didn't make it any better — far from it. The moment sodium hydroxide touched the lips, it burned the mouth and even the throat, and the damage was likely permanent. Which meant that from now on, Ms. Matsumoto might struggle to speak at all, let alone sing.
Ms. Matsumoto was a music teacher — and Ran and the others had mentioned before what a beautiful singing voice she had. The man hadn't set out to kill her; he had set out to destroy her voice outright. Xia Yu honestly didn't know whether "cruel" was even a strong enough word for him.
What could Ms. Matsumoto possibly have done, to make him repay a girl who loved him — who was about to marry him — like this?
Watching the shock on Xia Yu's face, Conan understood instantly: whatever was in that lemon tea had not been Xia Yu's doing. Which meant that someone really had drugged Ms. Matsumoto — and Xia Yu had known about it.
And there was only one person who could have convinced both Xia Yu and Ms. Matsumoto to hold back from exposing the culprit and arrange all this instead. Conan's gaze slid, slowly, toward the other principal of today's ceremony — the groom himself.
Meanwhile, the other officers were hard at work chasing down clues.
Seven people had entered and left the lounge in the moments before Ms. Matsumoto Sayuri collapsed: Conan, Ran, Sonoko, Umemiya-senpai, the bride's close friend Takenaka Kazumi, the groom Takasugi Toshihiko, and the bride's father, Matsumoto Kiyonaga. And according to the recording from the video camera that had been running in the bride's room the entire time, only four of them had touched the lemon tea in her hand — Umemiya-senpai, Takenaka Kazumi, Takasugi Toshihiko, and Matsumoto Kiyonaga.
Xia Yu had been carefully watching her surroundings since the moment she guessed something might go wrong today, and it was precisely because of that vigilance that she had caught the groom's small, furtive motion as he dosed the drink. That same attentiveness had also let her notice something else — before Ms. Matsumoto collapsed, she had picked up the wrong can: the lemon tea Sonoko had left on the table on her way out. Xia Yu had spotted it and was just about to say something when the groom came bursting in.
The cameras had recorded that too. Because of the camera angle, the two cans of lemon tea on the table looked like a single one, but on close inspection, the moment someone blocked the camera's view, the label on the can on the table had shifted direction. As a result, the poisoned can bore only three sets of fingerprints: Sonoko's, Matsumoto Sayuri's, and Takasugi Toshihiko's. And since Sonoko had drunk from that very can without coming to any harm, the drink couldn't have been poisoned yet at that point. Furthermore, sodium hydroxide deliquesces — absorbs moisture from the air and turns liquid — so before administering it, the culprit would have had to keep it in a glass vial containing a desiccant. That vial was later found by the police, abandoned in a trash bin in the hallway, indirectly proving that the poison must have been carried into the room by someone other than Matsumoto Sayuri. Eliminating the suspects one by one, the culprit could only be the groom.
Xia Yu had no intention of dragging out the big reveal. Once she saw that the evidence had been all but gathered, she simply named the killer in front of everyone, walking them through each piece of the chain as she went.
When Matsumoto Kiyonaga heard that the man who had harmed his own daughter was the groom from that very day's ceremony, rage boiled over in him instantly. He strode up to Takasugi Toshihiko and seized him by the collar.
"It was you! Tell me — why?! Why would you hurt my daughter?!" Matsumoto roared at him, shaking with fury.
Faced with evidence this damning, Takasugi didn't bother to deny it. He flung Matsumoto's hand off his collar, and with a look blending resentment and the dark joy of a long-awaited vengeance finally fulfilled, he said, "All of this is your fault. The only reason your daughter got hurt is you."
Then he told them what had happened twenty years before. Back then, Matsumoto Sayuri's father, in the middle of pursuing a fleeing criminal, had gotten an innocent mother and son caught up in the chase. But Matsumoto had been single-minded in his pursuit of the suspect and never noticed what he'd done — and the woman had missed her window for treatment and died. After his mother's death, the boy, who had no other relatives, was taken in by the Takasugi family. Seven years ago, Takasugi Toshihiko discovered that a close friend of his girlfriend was the daughter of the man who had indirectly caused his mother's death — and that was when he began drawing close to her, preparing to take his revenge for his mother.
So that was it. So that was Takasugi Toshihiko's reason for going after Matsumoto Sayuri.
Xia Yu had assumed that Matsumoto Sayuri must have unknowingly wronged him somehow, or that there was some misunderstanding between them. She had never imagined that the reason he made his move was her father.
And she found herself genuinely unable to follow the man's logic. Matsumoto Kiyonaga had indirectly caused his mother's death — fine, he hated him, so take revenge on him. What did any of this have to do with Matsumoto Sayuri?
Paimon looked puzzled too. "Traveler, why is the groom going after the bride? Miss Matsumoto never did anything to him, right?" She tilted her head, then ventured a guess. "Do you think maybe he wanted to make Inspector Matsumoto taste the pain of losing someone dear to him? As payback?"
Xia Yu hesitated. It can't be that, can it? He's supposed to be the heir to a whole corporation — surely even his revenge couldn't be this spineless...
"That's exactly what I wanted — to make you feel the pain of losing the person you love most!" Takasugi Toshihiko, watching the anguish twist Matsumoto Kiyonaga's face as the truth sank in, laughed out loud with open satisfaction.
Oh. So it really was that.
What was this supposed to be, then? Picking on the weak because he didn't dare face the strong?