If I just finish this, I can return to the year 3100. Repairing the time machine's engine. The formula is perfect, my condition is at its peak, and my heart is thumping like when I discovered a new law of conservation of mass.

I'll escape this filthy, germ-ridden, primitive year and go back home, get a girlfriend, and win a Nobel Prize as the greatest inventor. It's the ultimate path in life, right? Now all that's left is for things to bloom like a flower. Bye-bye to this trashy era— Goodbye my dirty—🎵

BOOM—!!!

U-Uwaaaah!!! F-Fuck...!! W-Why did it suddenly blow up... B-Based on the vacuum th-thrust calculations, it shouldn't have exploded here— Cough, cough!!! U-Ugh!!

Waving his hands to chase away the smoke rushing deep into his lungs, he simultaneously fumbled across the floor to find his gas mask. He grabbed the gas mask and pressed it onto his face... No, he put it on backward, cough!!! He grabbed the gas mask again and pressed it on so hard his skin felt chafed. Now he could finally think straight... Hurriedly feeling his whole body, he found dark powder rubbing off. Fuck. I have to clean again.

Turning his gaze forward, he swatted away the acrid smoke and stone dust blocking his view like chasing flies, and he saw something round. Huh? Huuuuh? When did a hole like that appear in the wall? It definitely wasn't there a moment ago. Because of the explosion? Anyway, it's a nearly perfect circle, as if he'd used the atomic-scale cutter he developed himself....

As the smoke clears, the scenery beyond the hole comes into view. A person? A small figure huddled and trembling. N-No way...!!

N-Next door!!!

W-Wait a minute.... V-Viruses!!! Unidentified viruses are!!! C-Contaminating the air in my house!!

Panic and fear rise simultaneously. Before that human could approach, he grabbed a blanket and ran toward the hole. Fortunately, the blanket was wide enough to cover the hole, and in an instant, a thin barrier was created between him and that primitive thing. Phew...

...And so, a pseudo-cohabitation with a primitive human, separated by a single blanket, began.