Who understands? He traveled through time with a high-spec spatial ability.

She hesitated for a moment, "I've only ever seen it in a banned book at the Imperial Medical Academy, and that book was stolen last year."

A cold glint flashed in Tantai Zhou's eyes: "The Imperial Hospital was robbed? The person in charge of the investigation at the time was none other than the eldest prince."

The two looked at each other, understanding each other tacitly.

After leaving the side hall, they decided to split up.

Qiao Jingjing entered the palace under the pretext of visiting the Empress, but in reality, she was investigating the source of the poisoned wine; Tantai Zhou went to the commander of the Imperial Guards to inquire about the security loopholes.

As dusk fell, the two met in Tantai Zhou's bedchamber. Qiao Jingjing took off her outer robe, revealing her inner garment soaked with sweat: "The Empress's palace is heavily guarded, but it couldn't stop me. That cup of poisoned wine was indeed problematic; it was a deadly poison called 'Heartbreak Powder,' which takes effect extremely quickly."

"Heartbreak Powder..." Tantai Zhou mused. "This poison requires 'ambergris' as a catalyst, but the palace's records on the distribution of ambergris..."

“There were unusual withdrawals at the First Prince’s residence,” Qiao Jingjing continued. “I checked the records at the Imperial Pharmacy.”

Tantai Zhou sneered: "I've also made some discoveries on my side. The commander of the Imperial Guards admitted that today's defense arrangements were adjusted according to the suggestion of the eldest prince, and guards were deliberately withdrawn from several key positions."

"Is the evidence conclusive?" Qiao Jingjing asked.

“Not enough.” Tantai Zhou shook his head. “Although my eldest brother covets the throne, he wouldn’t be so reckless. If Father and Mother were to die at the same time today, he would indeed be the biggest beneficiary, but the risk would be too great.”

Just as Qiao Jingjing was about to speak, she suddenly heard a soft sound outside the window. Tantai Zhou drew his sword with lightning speed, the tip pointing directly at the window frame: "Who's there?"

Silence reigned outside the window. Qiao Jingjing tiptoed to the window and suddenly pushed it open—a black cat leaped down from the eaves and quickly disappeared into the night.

"Wait a minute." Qiao Jingjing reached out and picked something up from the windowsill. "This is..."

It was a copper coin, but it had been bent by someone.

Tantai Zhou took it and examined it carefully. His expression suddenly changed: "This is the mark of the Second Prince! He liked to fold copper coins like this when he was a child. Later, it became the contact token for the assassins in his mansion."

Qiao Jingjing gasped: "So it wasn't an accident that the Fourth Prince bumped into you today..."

"That arrow was also aimed at me." Tantai Zhou gripped the copper coin tightly. "My second brother's mother was of lowly birth, and he endured humiliation and hardship from a young age. Everyone thought he was well-behaved and obedient, but unexpectedly..."

"Wait a minute." Qiao Jingjing suddenly thought of something, "If the Second Prince is involved, then the First Prince..."

A flash of realization crossed Tantai Zhou's eyes: "The eldest prince might have been used. The second prince knew the eldest prince harbored ambitions to seize the throne, so he deliberately leaked information to him, urging him to take risks, while he himself secretly fueled the flames..."

"Then they can reap the benefits," Qiao Jingjing continued, "If the Emperor and Empress were murdered today, the eldest prince, as the firstborn son, would be the most suspicious. Once the matter is exposed..."

"My second brother can ascend the throne as a meritorious official who quelled the rebellion." Tantai Zhou slammed his fist on the table. "What a brilliant plan to kill two birds with one stone!"

The night was deeper.

Tantai Zhou and Qiao Jingjing sat facing each other in silence, each pondering their own solutions.

The sound of a clapper came from outside the palace walls; it was past midnight.

“We need more evidence,” Qiao Jingjing broke the silence. “If we could find a direct connection between the Second Prince and the assassin…”

Tantai Zhou suddenly stood up: "I remember now! That flame tattoo! There's a musician from Northern Qi in my second brother's residence who has a tattoo like that on his hand!"

“We’ll split up tomorrow.” Qiao Jingjing’s eyes flashed with determination. “I’ll investigate the source of the poison, and you go find that musician. If there’s a connection, this person must have come with Prince Duan this time. But be careful, there are dangers everywhere in the palace right now.”

Tantai Zhou held her hand: "Jingjing, if it weren't for you today, Father would already be..." His voice choked with emotion.

The situation was urgent, and Qiao Jingjing didn't have time to think. As the emperor collapsed, she quickly took out an antidote pill from her spatial storage and stuffed it into his mouth.

This antidote pill is made from medicinal herbs and spiritual water from the upgraded spiritual field. In addition, Qiao Jingjing's alchemy skills have improved, making the refined antidote pill more effective than ordinary antidote pills.

A drop of her fingertip blood was also added.

She had no other choice but to try to control the spread of the toxin temporarily.

Qiao Jingjing gently squeezed her hand back: "Tantai Zhou, don't be sad, these are all temporary. Once things are over, I'll still cling to your coattails and run rampant in Daliang."

Outside the window, a blood moon quietly rose, enveloping the entire imperial city in an eerie light.

"Let's go, it's time for us to go see your father, but before we go, let me heal your injuries first."

Tantai Zhou raised his hand to stop him, "There will be imperial physicians with Father Emperor later, they will definitely want to examine the wound. Let them handle it."

The two rushed to Emperor Xuanjing's bedchamber, where they found the room brightly lit and the imperial physicians bustling about. Emperor Xuanjing lay on the bed, his face deathly pale and his breath faint.

The Empress had woken up and was sitting by the bedside, her eyes red and swollen, her expression sorrowful.

Upon seeing Tantai Zhou and Qiao Jingjing enter, the Empress forced a smile: "Zhou'er, Jingjing, you've come."

Tantai Zhou walked to the bedside and said softly, "Father, I'm here. You will definitely get better."

Emperor Xuanjing slightly opened his eyes and said with difficulty, "Zhou'er...you must...protect...the royal family..." Before he could finish speaking, he fainted again.

Qiao Jingjing felt a sharp pain in her heart when she looked at Emperor Xuanjing.

"Your Highness, please allow me a moment to speak," the imperial physician said tremblingly, bowing to Tantai Zhou.