Last man on earth when there is no earth?

Prologue. (Start of volume 03)

“I heard that Rooster doesn’t have much to see but…” taking a bite from her steaming hot bun, a young Zesionien female spoke. “It’s even less interesting than back home. I’m disappointed.”

“You say that but… you had quite a lot of fun yesterday, right?” A male replied, walking beside her with bags in his arms.

“Exactly!” She exclaimed. “The most interesting thing that happened here was meeting Ms. Lilia! I mean, I’m happy that we got to see her, but this is our first trip to another planet! Don’t you think that meeting an old acquaintance isn’t supposed to be the highlight of such event?”

“Yeah, I agree. But you see, Erika…” Digging into one of the paper bags he took out another bun. “You shouldn’t have gotten your hopes up, after all this planet is close to Zesion. It’s only obvious that not much would be different from the usual.”

The two walked down a street not much different from any found on their homeworld. The buildings had the same feel as what they were used to, same for the