I was woken up by the sound of Lin Yan rummaging through things in the morning of the fourth day.

Yesterday afternoon, after Lin Yan and I had sorted out our emotions, we went out to buy many books, fitness equipment, movie DVDs, and other entertainment supplies to pass the time at home in the future.

After dinner, he sat by the window on the balcony smoking and lost in thought. He rarely smokes, and the first time I saw him smoke was after his parents died in a car accident two years into our relationship. So, in this world, Lin Yan and I are truly dependent on each other.

He probably didn't sleep all night, I don't know, because I couldn't resist the sleepiness, I sat on the sofa to accompany him, and fell asleep sitting there. When I woke up, I was already in the big bed in the room.

Walking out of the room, I saw Lin Yan installing sound-absorbing panels on the walls of the house.

"Are you awake? I bought youtiao and soy milk downstairs for breakfast. They might be a bit cold, warm them up before eating." Lin Yan glanced at me and continued to install the sound-absorbing panels on the wall.

"Why are you installing sound-absorbing panels?"

I was puzzled, after all, we live on the twenty-third floor, so any noise downstairs would definitely not be heard. Therefore, when we were buying supplies, I didn't think about installing sound-absorbing panels in the house, I didn't think it was necessary.

After Lin Yan installed the last piece of sound-absorbing panel in the living room, he looked around the living room, warmed up breakfast for me, and said, "I carefully checked the things you bought last night, and although there are many power banks, they are not practical. If the city runs out of electricity and water, these power banks without electricity will be useless. So I went out and bought a solar power generator and a solar water pump. Although we are on a high floor, once it becomes a ghost town, any noise will be very noticeable. Anyway, you said that money won't be worth much at that time, so let's be even safer."

I took a bite of the warm youtiao and gave Lin Yan a thumbs up.

"By the way, did you notice anything unusual when you went out today?"

"Not for now. I walked around and found that the supplies in the city's supermarkets have been basically wiped out by the masses. There are still a lot of people today, all going to grab supplies. The pharmacies have also been cleaned out. In short, anything you can think of, people have already thought of." He pulled a chair and sat across from me, drinking soy milk and talking to me.

"Fortunately, we have a 'frontline' worker in our family, otherwise we probably wouldn't be able to stock up on so many supplies."

"Well," he sighed, "Li from the office told me today that there have been confirmed cases in City B."

Sure enough, not an ounce off from my calculations.

"Fortunately, A City has not been found infected for now, so we should be able to stay safe for a couple more days."

My words didn't get Lin Yan's agreement when they came out, which made me confused. I looked up to see him frowning.

"Actually... there might not be two more days." He looked at me and continued, "Although they have controlled the infected cases in City B, after checking his itinerary, they found out that he had just come back from A City to B City two days ago. We still don't know how the infection spreads, so A City is not safe either."

The youtiao in my mouth suddenly didn't taste good anymore...

"If it spreads through the air, do you need to quarantine after going out today?"

Lin Yan gave me a glance, "If it spreads through the air, the first city to discover infected cases, City C, would have fallen long ago. So I think it's unlikely. It's more likely to spread through food."

"Why do you say that? Because the chickens and ducks are mutated?"

"I'm just guessing. Because the carriers of this kind of virus were first found in mutated animals, and then to humans."

"Then how did the animals get infected with this virus?"

For a moment, Lin Yan and I were both lost in thought. There must be a specific medium that caused the spread of this virus, but what could it be?

The meowing sound of Niko leaning against the glass door of the balcony interrupted our thoughts. I walked to the door and looked through the glass, only to see that the lone goldfish in the pool had turned belly up.

"Yesterday this goldfish was still swimming lively and vigorously. When Niko wanted to claw at it, it was still fluttering and dodging, very agile. How could it suddenly die?"

Lin Yan stared at the continuously running water pump in the pool without saying a word, then turned back into the room to get something, reminding me not to touch the water in the pool.

I chased Niko back into the house, and Lin Yan happened to come out with a test paper in his hand.

He dipped the test paper into the water, and the paper gradually turned from white to black, but the water in the pool was still clear.

Lin Yan and I looked at each other and said in unison, "Water!"