Trying to return from Forthorthe 2,000 years ago to present day Earth, Koutarou and Clan had a big problem, and that was that the spaceship, the Cradle, had broken down and couldn't fly through space.
The part of the ship that had broken down was a small part, and as long as Clan could get her hands on a replacement, she could finish repairs within five minutes. But that part wasn't something she could get her hands on in the past Forthorthe. That's why Koutarou and Clan had to wait until it started getting produced.
There were two things they needed in order to be able to wait for 2,000 years. That was the technology to stop time, and a place where they could wait for 2,000 years. The former was something the Cradle was equipped with, and Clan had an idea for the latter.
That place was called 'Bertorion's special territory'. Koutarou and Clan would hide the Cradle in an area that Alaia would later declare as an inviolable domain. They would then freeze time on board the ship and wait 2,000 years.
“It's over.”
“Are you sure? It doesn't feel like anything happened...”
“That's only natural. The time onboard was frozen after all.”
It didn't feel like time had stopped to Koutarou. Clan had been busily working on her operator's panel, and nothing similar to what he had thought would happen occurred.
“I thought it would glow or shake or something.”
“I think that happened, but since we were frozen in time, we couldn't perceive it.”
“So we're 20 years in the past now?”
“That's right. If you step out, you'll see.”
Using the Cradle's ability to distort space, Clan had altered the speed at which time progressed inside the ship and outside. With that, a single moment onboard was 2,000 years outside. Glowing and shaken had occurred at the very start, but it only lasted for a few seconds on the outside, and it wasn't long enough that Koutarou could perceive it inside.
“However, it isn't exactly 20 years.”
Clan continued to busily operate her panel while explaining to Koutarou. She had to confirm the Cradle's current condition and the likes, so there was a lot to do.
“What do you mean?”
“People celebrating the 2,000th anniversary of Alaia-san's ascension to the throne might come if we arrive at precisely the same day we came, right? I set it so that we'd arrive a little before the ceremony.”
“I see.”
While 'Bertorion's special territory' was an inviolable domain that Alaia had created and entry was forbidden, it didn't mean that people wouldn't enter. People from the Pardomshiha family, who were in charge of managing the territory, would patrol the area, and people from history programs would get permission to shoot inside, as long as they didn't disturb the environment.
And since 20 years ago was the 2,000th anniversary of Alaia's ascension to the throne, the amount of people would inevitably increase. That's why Clan adjusted the time so that they wouldn't come into contact with someone.