The first signs

The dead rat had definitely entered the space inside the backpack.

Before Su Jin could even process it, wild joy seized him!

A new notification had already appeared before his eyes.

[Recovery successful. Exchanged for an item of equivalent value.]

Hell yes!

The company might be blunt and heavy-handed, but its efficiency was beyond reproach!

Secretly delighted, Su Jin hurriedly reached into the backpack again.

After feeling around briefly, he pulled out a black cardboard box.

For some reason, the small box in his hands made Su Jin nervous.

Apart from the supplies the company had given him at the start, this was his first real interaction with it.

There was the mask, which seemingly let him communicate with the company and translate without any barriers.

Then there was the backpack with its own independent space.

And a handgun that needed no magazine changes, though he had yet to test it.

This new item had to be something extraordinary too!

After taking a deep breath, Su Jin opened the black box with eager anticipation, making quite a ceremony of it.

The lid came off, revealing a flash of silver.

It had smooth, rounded curves.

A streamlined metal object with the look and feel of titanium alloy came into view.

The corners of Su Jin's mouth slowly drooped.

His hand trembled as he took the item out of the box to examine it.

After just two glances, he completely lost it and slammed the box onto the floor!

"Holy! Shit!"

"What the hell is this?!"

Holding the metal plug from the box, Su Jin shook with outrage.

Fuck!

This was beyond a joke. They had actually sent him a toy!

He was already anxious and panicked enough.

The world was ending, and the company sent him this damned thing? What fucking use was it?

After a bout of furious cursing, Su Jin's emotions subsided.

Holding the item he had just received, he felt utterly desolate.

He was stuck with a company this unreliable. They didn't care whether he lived or died!

I never should have gone drinking with that client. If I hadn't gone with the client...

In the midst of his self-pity, Su Jin abruptly snapped out of it, his gaze fixing on the floor.

A card had popped out beside the black box he had thrown down. Was it an instruction sheet?

Could this be a misunderstanding...? The company was a supernatural entity, after all. There had to be some misunderstanding!

Su Jin hurriedly picked it up to read.

[First-aid suppository. Contains emergency medication, automatically released upon detection of a drop in body temperature. May be used repeatedly until the medication is depleted. A burning sensation is normal. Do not panic.]

[If entering a dangerous situation is unavoidable, insert in advance to prevent life-threatening circumstances from making timely use impossible. Do not forcibly open the casing. The medication readily loses its efficacy and is intended for rectal use only. Oral ingestion carries an extremely high risk of poisoning.]

"Couldn't you give me some halfway decent medicine?!"

Furious, Su Jin slammed the instructions onto the floor.

So it was a suppository... Absorbed through the mucous membranes, bypassing the liver's first-pass effect. Faster-acting than oral medication and steadier than an intravenous injection.

But turning this thing into emergency medicine was just ridiculous!

After calming down for ten minutes or so, Su Jin found some nylon cord, secured the first-aid suppository, and tied it to his waist.

He absolutely wasn't going to use it himself. Considering that someone around him might end up in danger, he would keep it ready for now.

The experiments still had to go on. Once he had calmed down, Su Jin took out two more rats for infection tests.

The rat he had put in the running wheel earlier had already changed. It was now constantly launching suicidal charges at him.

Trapped inside the wheel enclosure, however, it could only keep running in place.

After crouching down to observe it for a long while, Su Jin picked up his notebook and began recording his findings.

The gray substance in the rain was definitely the source of the mutations, but the speed of infection correlated strongly with the amount of gray substance absorbed.

For now, all he could tell was that this substance had an extremely high infection rate.

There was no way these crude, amateur experiments could determine the actual probability of infection. He also lacked enough rats to test.

The infected rat's mobility had declined significantly. Its limbs were somewhat mechanical, and it didn't run fast, but it never tired and felt no pain...

After making a few brief notes, Su Jin took out some batteries and put them into the miniature four-wheel-drive car.

The motor started, driving the wheel enclosure into motion.

The mutated rat clearly couldn't quite keep up. It tumbled around inside the cage, but he could still see its intense determination to right itself and attack.

A little over twenty minutes later, the batteries ran out. He replaced them with another set and kept it running.

Only after draining five consecutive sets of batteries did Su Jin stop and switch to turning it by hand.

As he turned the wheel enclosure, Su Jin couldn't hide the disappointment on his face.

The conclusion was deeply discouraging... The mutated rat's stamina had barely diminished. It had even grown a little stronger, seemingly adapting to its body as time went on.

Another hour passed.

After experiments involving confinement, burning, drowning, drilling, and more, Su Jin's spirits hit rock bottom.

It couldn't be suffocated or drowned. Even after its entire body had been burned to charcoal, it could still move slightly.

Infected creatures possessed terrifying resilience. Only piercing the torso caused rapid death. Even cutting off the head didn't kill it.

Since he didn't understand a rat's anatomy, he hadn't figured out exactly which spot had to be pierced. He only suspected it was the heart.

The only two things he had yet to test were how long it could survive and whether it could infect others of its kind.

But by now, Su Jin was exhausted in both body and mind.

He picked up the rat cage, placed it in the glass aquarium he had bought earlier, covered it with a wooden board, and went straight back to the bedroom.

In the darkness, another radio, already tuned to the AM band, came to life.

Su Jin forced his eyes open and hurriedly adjusted the radio.

FM was mostly used for local broadcasting, with limited coverage and a focus on entertainment; AM, with its long range and resistance to interference, was often used for national or emergency broadcasts, making it the preferred communication band during a disaster.

Although this wasn't Earth, its technological development had followed a similar path. Electromagnetic waves worked the same way in both worlds, and he had already done his homework.

Now that the radio was broadcasting, the authorities must have detected something wrong and issued a nationwide warning.

After a few adjustments, the broadcast gradually became clearer.

Hiss-crackle-

"...You are now hearing the latest bulletin from the National Disaster Emergency Command Center. All citizens must pay close attention-"

"As of one o'clock this afternoon, most regions within the country have been affected by rainfall of an unidentified type. The affected area is extensive... This rainfall presents potential biological hazards and may cause irreversible effects through contact with the skin, respiratory tract, or digestive system."

"Sudden incidents involving groups of people losing control in multiple locations have now been confirmed to be associated with this rainfall. Abnormal individual behavior..."

"All citizens must immediately comply with the following orders: one, do not come into direct contact with rainwater in any form; two, use only bottled water or water from securely sealed sources for drinking and cleaning; three, immediately seal all doors, windows, vents, and drainage systems to prevent any intrusion of outside water or moisture."

"These directives take effect immediately upon broadcast. Anyone refusing to comply will be deemed a threat to public safety... Further updates will be released simultaneously through radio broadcasts and online channels."

After listening to the announcement, Su Jin felt his spirits lift and let out a long breath.

Thank goodness... The state's machinery of force was about to get moving!

Clearly, the authorities had fully recognized the terrifying severity of the Gray Rain and issued direct instructions for action. That alone showed how urgent the situation had become.