The Three Kingdoms: The entire Cao Cao camp thought I was weak and frail.

Guo Jia smiled with satisfaction. This little guy was becoming more and more able to follow his train of thought.

As the sun gradually set, the Yellow Turban army's offensive remained swift, seemingly intending to storm into the city for the night. Just then, from the hills behind the Yellow Turban army camp, came the faint sound of horses' hooves.

At first, the sound was faint, almost an illusion. But soon, the sound of hooves became more frequent, like muffled thunder rolling, approaching from afar. Immediately afterwards, a cloud of dust rose into the sky.

"What's that sound?" A patrolling Yellow Turban soldier stopped and looked back in confusion.

"It sounds like horses' hooves..." another person said, their voice trembling slightly.

The sound of hooves grew louder and more urgent, as if a thousand troops were charging from behind the hills.

Dust obscured the setting sun, shrouding the entire mountain in gloom, making it impossible to discern the real from the fake.

"Enemy attack! Reinforcements have arrived!" Someone shouted first, instantly igniting the tense atmosphere.

"Thump! Thump! Thump!"

The deep sound of war drums came from the depths of the hills, accompanied by the deafening sound of horses' hooves, like a death knell, exploding in the Yellow Turban army camp.

Bo Cai's generals, upon hearing the commotion from behind, all paled. They knew that Huangfu Song and Zhu Jun's reinforcements were nearby, but they hadn't expected them to arrive so quickly, and to launch a surprise attack from their weakest point—the rear!

"Quickly! Go and report to the commander!"

"Assemble the troops! Prepare for battle!"

The entire Yellow Turban army camp instantly descended into chaos. Soldiers were jolted awake from their sleep, frantically grabbing their weapons and running in all directions.

Inside the central command tent, Bo Cai rose, his armor clad, his face ashen. He heard the tremendous noise coming from behind him and felt a surge of surprise and doubt.

This display of force could not have been created by a small force. Could it really be reinforcements from the imperial court? But how did they manage to get around to our rear?

"Commander! A large enemy force has appeared in the rear! Dust fills the sky, their momentum is immense, and they may number ten thousand!" A messenger rushed into the tent, his voice trembling with tears.

"Ten thousand men?!" Bo Cai's heart sank. He had thought that with their numerical advantage, they could quickly attack Yangdi and then fight Huangfu Song in a decisive battle. He never expected that his rear would be attacked!

"Sound the retreat and withdraw ten miles to the left!" Bo Cai roared through gritted teeth. He knew that if his 50,000 troops were attacked from both sides, they would be in dire straits.

However, fleeing without a fight would greatly impact morale, and besides, they were indeed running low on supplies.

Guo Jia stood on the high slope, watching the Yellow Turban army gradually retreat, a smile playing on his lips.

"It's done," he said softly, a hint of pride in his voice.

"Now, it's time to go into town."

"Brother Fengxiao," Xun Hao's voice rang out beside Guo Jia, "I remember when I was a child, my grandfather took me to visit Yangdi City. In the southeast corner of the city wall, there was an abandoned flood discharge culvert. Its entrance was below the surface of the moat, and its exit led directly to a deserted garden inside the city."

Upon hearing this, Guo Jia paused, looking at Xun Hao. His eyebrows twitched slightly, a hint of surprise flashing in his eyes. This little fellow even knew such a secret detail? He suppressed his curiosity and pondered the feasibility of this hidden channel.

"A hidden channel?" Guo Jia pondered. This was indeed a surprising solution. "Is the channel still usable? Where is the entrance? And where does the exit lead?"

Xun Hao nodded: "The underground channel has not been used for many years, and its internal condition is unknown. However, the garden where its exit is located has long been abandoned and rarely visited, making it difficult to find. The entrance is below the surface of the moat, marked by a rock shaped like a reclining turtle."

"Good!" Guo Jia immediately decided, "Let's take this underground channel! Send the order: fifty of our best swimmers will follow me. The rest of you, stay put and create a disturbance. Don't let Bo Cai suspect anything."

The water in the moat was even colder than I had imagined.

Guo Jia plunged into the water, instantly feeling every pore on his body contract. He endured the discomfort and opened his eyes wide, searching the murky water.

Underwater visibility was extremely poor, with floating seaweed and silt everywhere. Forget about finding any culvert entrance, you couldn't even see your own hand.

On the shore, Xun Hao was wrapped in Guo Jia's cloak, which still held the warmth of his body, and was shivering from the cold, but he forced himself to remain absolutely conscious.

He tried hard to recall the times his grandfather had taken him to play there when he was a child, and exactly where that turtle-shaped reef was located. If that didn't work, he still had his last trump card.

"Brother Fengxiao, go three feet to the left, there should be a large rock underwater!" he shouted towards the water.

Upon hearing the sound in the water, Guo Jia immediately adjusted his direction. Holding his breath, he dived to the bottom again and again, groping around in the mud with his hands.

Time passed second by second, and the sound of splashing water could be heard from the river surface from time to time. It was the sound of Guo Jia and his guards diving into the water and then surfacing to breathe.

"Young master, the underwater silt is too thick and the water plants are tangled, we can't see anything at all!" A guard surfaced, his voice tinged with anxiety.

Guo Jia wiped the water from his face, didn't respond, and dived back into the water. He knew they had no way out.

Just then, a strange movement came from underwater. A guard's feet got tangled in the water plants, and he nearly drowned. Guo Jia reacted quickly, grabbing him and pulling him to the surface. The guard was panting heavily, his face filled with terror.

"Watch out!" Guo Jia said in a deep voice, diving down again. After several dives, finally, at a depth of two feet, his hand touched a cold, hard object. He pushed aside the thick seaweed and silt, and sure enough, a rusty iron fence appeared before his eyes.

The iron fence was secured by underwater iron chains, making it exceptionally sturdy. Guo Jia tried to pry it open with his dagger, but it wouldn't budge.

"Brother Fengxiao!" Xun Hao, on the shore, leaned his head into the water, his voice tinged with urgency. "Grandfather once said that the lock is a three-linked mechanism that requires all three links to be turned at the same time!" He tried hard to recall and described the general structure of the mechanism to Guo Jia. It was a unique lock of the Xun family that outsiders could not possibly know about.

Guo Jia understood. He surfaced and relayed Xun Hao's description to the other two guards who were the best swimmers. The three exchanged a glance and then dived back into the icy river.

Underwater, the three of them worked together, following Xun Hao's instructions, to grope for the mechanisms on the iron fence in the darkness.

The icy water washed over their bodies, and the heavy iron chains wrapped around their hands made their movements extremely difficult.

"Click!"

A soft sound, remarkably clear underwater, rang out. The iron gate opened in response, and a stream of water, mixed with silt and the stench of decay, gushed forth from the culvert.

"The entrance is open!" Guo Jia surfaced, panting heavily, his face showing a hint of exhaustion but unable to hide his excitement.

He ordered the guards to escort Xun Hao inside first, while he stayed behind to cover the rear.

Supported by his guards, Xun Hao carefully entered the underground canal. A cold, damp atmosphere rushed towards him, making his already weak body feel uncomfortable.

The inside of the culvert was pitch black, allowing only one person to pass by bending over.