Starting from Robinson Crusoe

...

Every day they had to walk dozens of kilometers, and Paul’s knee recovery was relatively slow.

But the situation was urgent; he knew the severity of the problem well and refused to maintain the previous pace, insisting on increasing the travel time.

Fortunately, there were many mounds and ravines on the grassland to take shelter from the wind. Dry grass quickly ignited, and every certain distance one could encounter a forest. The active animals were numerous, making the overall environment much better.

Even if they walked an extra hour or two, because they rested better at night, it was actually less exhausting than walking on the tundra.

Continuing in this way, within a few days, the two arrived at a familiar place—

Chen Zhou arrived at the forest of the Prehistoric World, also the place where Paul first began his challenge, facing the Cave Hyena.

...

They did not intend to revisit the old place nor had the mood to rest here. Neither Chen Zhou nor Paul wanted to walk into the forest; they just skirted the edge, trying to find a few good trees for making gunstocks, and continued on their journey.

After all, time waits for no one.

Along the way, the two noticed that most of the prehistoric creatures from the islands or the mid-latitude, equatorial regions had died.

The banks of the river were littered with the skeletons of various animals.

The environment and native fierce predators sounded their death knell. Even if some animals escaped a disaster, they were barely surviving. When the real harsh winter arrived, let alone these "outsiders," even the native creatures might not survive the entire winter.

Even with the exclusive "cheats" provided by the Space-Time Administration Bureau, thinking about the terrifying number of minus sixty-five degrees, neither Chen Zhou nor Paul felt confident in surviving.

They both wished for wings to fly back overnight to the hard-built semi-permanent shelter or shuttle between the Black Forest and the southern shelter with every effort to transport coal to survive the harsh winter.

...

The shuriken flipped between his nimble fingers, and Chen Zhou was looking for a suitable gunstock for it when suddenly Tiger Third leaped beside him and ran into the forest.

"This little guy..."

Chen Zhou sighed helplessly, watching the coal Tiger Third tossed out. Like an old father worried sick, he hurried to pick it up.

The precise cold was a lullaby for humans but an excitant for the Saw-toothed Tiger.

The colder it got, the more excited these three guys became.

As their bodies grew bigger, their courage increased day by day. Sometimes when Chen Zhou and Paul started a campfire, they would sneak away together to run far, or to chase prey, or to run and play, practicing hunting skills.

Initially, Chen Zhou tried to restrain them with orders, but later he realized that exploring the world was engraved in their bones, so he no longer forced them to stay around.

But before letting them go play, it was always necessary to unload their "little backpacks," otherwise no amount of coal would be enough for them to throw around.

Seeing Tiger Third running into the forest, Chen Zhou initially thought it had spotted some small animal or was acting playful, so he didn’t bother controlling it much.

Unexpectedly, shortly after it ran into the forest, it came out holding a camouflage hat in its mouth.

The hat was large, with a high, pointed top, a red five-pointed star sewn on the front, and pull-down ear flaps made of wool, with a typical early 20th-century style.

Likely having been in the forest for too long, subjected to wind and sun, the woolen fabric originally a deep brown had faded, with various depths of color, and the ear flaps bore some tearing marks with faint black and red bloodstains visible.

Holding the hat tightly, Tiger Third wagged its head and tail, presenting its trophy to Chen Zhou as if seeking credit.

Chen Zhou didn’t find anything special about the hat, just thinking it might have been left in the forest by some other challenger, but Paul beside him became agitated, limping two steps to Tiger Third and grabbing the hat.

He eagerly patted away the dry leaves and grass stems on the hat, inspecting it repeatedly, incredulously muttering to himself.

"General Gromov?"