We headed to the forensic laboratory where the lab assistant was studying something through the microscope. Upon noticing us, he was just about to greet us when Xiaotao said, "Don’t worry about us, carry on with your work. I'm just here to grab some glucose solution for a case."

Xiaotao grabbed one of the bottles and we walked back to the Necropsy Workshop, ready for further testing. 

I pierced the top with a sterilized awl, poured some into a container and tasted it. It turned out that glucose tasted normal so it was the protein we couldn’t stomach.

"Remember the case where our suspect was mistaken for a vampire because of a protein metabolism disorder. Could it be a similar kind of disease?" suggested Xiaotao.

At the thought of the pale vampirish man, I shook my head, "That’s impossible. Protein metabolism disorder is a genetic disease that produces an allergic reaction with the intake of certain proteins. That’s completely different from not being able to stomach meat. Ours is a problem with taste. Besides, we ate meat in the afternoon and we’re fine."

"Why wasn’t there a reaction during lunch?" asked Xiaotao.

"Perhaps our bodies hadn’t absorbed the poison at the time," I speculated.

Even with further contemplation, I was still scrambling to make sense of it all. What was the point of such a poison? Xiaotao began tidying up the workshop, accidentally cutting her finger in the process. As she clutched her finger, I said, "Don't move, I'll get some iodine to disinfect the wound."

"It’s a tiny wound," she argued.

She slipped her finger between her lips and sucked on the blood. As I explained how easy it was for the wound to get infected, I reached for the iodine. But just as I turned around, a thought suddenly crossed my mind. Noticing the look on my face, Xiaotao asked, "What’s wrong? Why are you looking at me like that?"

"Don’t you feel sick when tasting your own blood?" I queried.

"Not at all,” Xiaotao shook her head. “Is there protein in blood?"

"Yes, a very high content of it!" I said.

"I don’t have the slightest bit of nausea. In fact, it tastes sweet!"

As soon as the words fell from her lips, I had a bad guess as to what the poison did. To verify my hypothesis, I grabbed a sterilized knife, sliced my finger, and tasted my own blood. An attractive flavor spread across my tongue, accompanied by an indescribable sweetness. 

I reached out so Xiaotao could taste my blood as well. A moment later, she covered her mouth with shock and cried, "Goodness, why does your blood taste so good?"

"My blood doesn’t taste good. It's the poison interfering with our taste buds that makes the brain think human blood tastes good."

"But is the protein in human blood any different from the protein in milk?"

“Of course."

Recalling what happened in the steakhouse earlier, I wondered why the steak tasted so bad. The proteins in human blood and bovine blood could be said to have the same composition. But strictly speaking, every species had its own unique biological enzyme. Therefore, our bodies produce a sense of aversion when we eat our own kind to prevent this sort of behavior.

"The problem doesn’t lie with the bottle of wine but with the person who delivered it. He definitely has ulterior motives."

"I’ll call my dad now!" said Xiaotao.

Upon realizing she couldn't get through to her father, Xiaotao phoned home. The housekeeper, Mrs. Zhang, said Mr. Huang went out with a friend in the evening. When Xiaotao asked who that friend was, the housekeeper reported it was Mr. Mu, the man who gifted Mr. Huang the bottle of wine.

As soon as she hung up, Xiaotao left the Necropsy Workshop and headed to the technical department to get them to locate Mr. Huang’s position through his cell phone.

As long as his cell phone was on, it could be tracked. Unfortunately, Mr. Huang’s cell phone was completely unreachable. I comforted an anxious Xiaotao, "Don't worry. Nothing will happen to a good man like your father. Let’s start from the clues we have now."

"Alright, let’s get Bingxin to test the bottle of wine!"

We drove to Sun Tiger’s home, where Bingxin was already waiting for us downstairs. "How did you get your father to agree to let you out at night?" I asked.

"I said Xiaotao-

jiejie

 had a super urgent task and I had to go," she smiled. “Besides, I’m a member of the special team now!”

“Up to your little tricks again, huh?" I snorted.

Xiaotao drove in somber silence, too troubled for jokes.

When we arrived at Mr. Huang's home, Mrs. Zhang came to welcome us. I instructed Bingxin to take the entire bottle back for testing since it was our only clue at the moment. The fingerprints on the bottle and the producer were also worth investigating. Before leaving, I made sure to grab one of Mr. Huang’s glasses that had his fingerprints on it. 

"Do you remember what I did when Li Wenjia asked me to make a choice? I chose to sacrifice my dad," Xiaotao recalled as we were headed downstairs.

Well aware of the significance of her words, I consoled, "You don't have to feel guilty about it. That gave you no choice.”

Xiaotao shook her head, "How can I feel any less guilty? Since then, I’ve realized what a failure of a daughter I am. I keep hoping to make it up to my dad. All I want is for him to be safe and healthy. But who would’ve thought he’s involved in something again..."

"Xiaotao-

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, my dad often stays out the whole night. It’s probably nothing."

"That’s easy for you to say now,” scoffed Xiaotao. “When your dad was hit by a car, didn't you cry?"

"Alright now, let’s not think of the worse,” I mediated. “We’ll do what we can given the circumstances."

"What else can we do besides test this bottle of wine?" Xiaotao asked.

"When I first entered his apartment, I noticed several ties thrown on the sofa, a pair of leather shoes missing from the shoe rack, as well as the walking stick originally hanging on the clothes rack. It must be a formal occasion if he’s wearing a tie and leather shoes. Judging from this, we can at least speculate that he wasn’t kidnapped,” I explained. “By the way, did he leave in his own car?"

“No,” Xiaotao shook her head.

"That means a friend picked him up. It’s definitely not a meeting given the time of day. Perhaps he’s attending a private party or banquet. You can inquire about this from your father's social circle."

"But why can’t we track his cell phone?"

"Maybe there’s a signal jammer on scene so we can’t reach him. Some high-end clubs do have that feature."

"Your analysis does sound reasonable,” sighed Xiaotao. “Maybe my dad is fine after all."

My words were meant to comfort but they were far from the truth. It was highly unlikely that nothing had happened. However, perhaps it wasn’t the sort of accident we imagined. Whoever produced that bottle of wine that made human proteins taste delicious definitely had skills beyond the average person. Additionally, the mastermind must have a purpose. 

I feared Xiaotao might have to handcuff her father after knowing what he did tonight!