Deadly Game: The Mysterious Sister

As a devoted older sister, Qian Yu sets off to search across worlds after her two younger brothers go missing. After traveling through who knows how many worlds, she finally finds them in a world under invasion, only to discover that each brother's fate is more miserable and mysterious than the other's.

Qian Yu says, "Great, time to take up my old line of work again. Can't I get a little break?"

Note: This combines the book and the drama. The couples won't be split up. I'll do my best to make up for the regrets, though the characters may be out of character.