I surfaced and recounted the situation beneath the water to them. Li Xiaohao remained silent. Bai Huaqian nudged me with his flashlight, saying, "The antidote is with Xiaohao. The outside is swarming with zombies. Don't try any tricks. Dive in and see where that opening leads."

Patience is key to a greater strategy; I swallowed their threats, took the flashlight from her hand, took a breath, and sank back into the water, swimming directly toward the cavern entrance.

In the Sea of Lost Souls, people don't need to breathe; you can stay as long as you wish without the threat of suffocation. But here, it was different. This pool was just ordinary water; I could only stay submerged for a minute or two before needing to surface for air, or I would drown. Therefore, I had to be fast, locate the exit on the other side in the shortest possible time, and replenish my oxygen quickly. If there was no exit on the other side, I had to return here before my strength and oxygen reserves were completely depleted.

I roughly calculated my limits underwater: the length of that tunnel couldn't exceed twenty meters, or the passage would become my tomb.

The flashlight beam illuminated the cavern mouth, but visibility wasn't great. The walls of the tunnel, like the walls of the pool, were smooth and slick, seemingly carved by human hands. I tucked the flashlight vertically into my shirt pocket and began swimming forward, pushing against the slick walls with both hands. Along the way, one or two small fish darted past me—a rare sight. Fish are usually incredibly astute, especially in places like this, undisturbed and sunlight-deprived for years; the slightest movement sends them fleeing far away. Yet, these two had brushed right past me!

After swimming another dozen meters, there was still no sign of an exit. I swept the beam ahead, illuminating nothing but inky blackness. My chest began to feel tight. I hesitated between turning back or pressing on. Returning empty-handed would certainly be unfortunate, but continuing might mean I wouldn't be able to get out. However, if I couldn't save my elder sister, living alone in this world held little meaning anyway. With that thought, I continued swimming forward.

After a few more meters, the passage widened slightly, enough for two people to swim abreast. But the symptoms of oxygen deprivation were becoming pronounced: my limbs felt heavy as lead, and the urge to draw breath grew stronger, requiring immense effort to keep from inhaling. I reached upward, trailing my hand along the tunnel's ceiling, hoping to feel the water surface. Even a centimeter of space between the water and the top of the tunnel would allow for a gasp of air. But the water completely filled the space.

Turning back was no longer an option; I could only force myself onward. After a while, my fingers touching the walls began to grow numb, and my vision blurred. My lungs were completely devoid of oxygen, and I advanced slowly, relying purely on willpower. While no one would simply stop breathing, the moment control was lost, a flood of water would instantly rush into the stomach and lungs. At that point, drowning here would be a certainty.

Gradually, my strokes slowed, my kicks weakened, and my consciousness faded. For one terrifying second, I sank straight to the bottom, paralyzed. Just then, a hand reached out from ahead and grabbed me. I opened my eyes but couldn't see clearly, only feeling a finger touch my lips, as if urging me to hold on.

I mustered the last reserves of strength I had, holding my breath, and allowed that hand to pull me forward. After swimming perhaps two or three meters, the direction shifted from forward to upward. The owner of the hand seemed to be a man, and he pulled me vigorously toward the ascent.

One second, two seconds, three seconds... I silently counted, desperately maintaining control over the floodgate in my chest. By the count of twenty, my head felt three times its normal size, and the need to breathe overwhelmed everything. Life or death, I didn't care anymore. I suddenly opened my mouth and inhaled deeply! Simultaneously, two palms braced my arms and pushed me up to the surface. Air, mixed with spray, instantly flooded my lungs.