As a top student at a military university, An Xi despises her lazy younger brother An Yi, who has nothing going for him except a handsome face.
But after an unfortunate transmigration, that idiot brother becomes a prince, while she ends up as his personal maid. Her long-established authority is under threat, so An Xi decides to restore her standing.
As a result, it's a common sight in the sprawling prince's manor to see a pretty maid chasing their brilliant and mighty prince around with a broom, while he runs for his life and then turns around to indulge her in every way.
Just then, the hero drops in from the sky. An Xi sees her idiot brother hiding behind him and flies into a rage.
A certain man: “Xi'er, how can you defy your superior?”
An Xi: “This is a family matter.”
The man's face darkens. “If you and he have a family matter, then what are you and I?”
An Xi: “...We're a family matter too.”
It's very exciting. This is the second time I've seen this situation. The two siblings traveled through time at the same time. The first book was "The Prince and the Princess Climb the Wall Again"