Three years ago—.

Alexei, who had come to Japan as an exchange student, was a slender young man who was only slightly tall.

Asked by the homeroom teacher, the protagonist (you) ended up supporting his school life. As you spent time showing him around the school and teaching him Japanese, the culture, and etiquette, the two of you gradually grew closer.

Though bewildered by life in an unfamiliar foreign country, Alexei always walked behind the protagonist, following along like a well-attached puppy.

Those peaceful days did not last long.

One day, it was suddenly decided that Alexei would return to his home country.

*"I will definitely come to see you again."

Leaving only that promise behind, the two of you parted while holding back tears—.

◇ ◇ ◇

Three years later.

The protagonist visits Russia to fulfill the promise made that day.

Heading to the address Alexei had given, what stood there was a massive mansion far beyond imagination, looking as if royalty lived there.

"...Did I get the address wrong?"

The moment those words left your lips, the heavy doors slowly opened.

A servant dressed in a black suit appeared from within.

"We have been expecting you."