The joke is that Asahi has zero power in a fantasy world built for overpowered protagonists, and the show actually commits to that being funny instead of tragic. His sister Maya demolishes everything with one hit, and instead of resenting her, he becomes the person keeping her grounded, which is the opposite of every isekai you've watched. The comedy lands because it's not trying to be clever about subversion, it's just watching a useless guy figure out his actual value while his sister casually warps the entire power dynamic of the genre.

Asahi gets his wish when he's suddenly transported to a fantasy world straight out of the games and novels he loves. The problem: he arrives powerless, with no special abilities to speak of. Just as panic sets in, his older sister Maya appears at his side, and she's won the cosmic lottery. She possesses absurdly overpowered skills that let her obliterate any threat in a single strike. Overjoyed to be reunited, Maya vows to keep her little brother safe no matter what, and the two set out to find a way back home while making the most of their new lives. Yet their arrival may not have been an accident, and as the Demon King's mighty army draws near, Maya looks like the only one capable of holding it back. The result is a comedy fantasy with a touch of romance, powered by an ordinary boy and the doting sister who can end any fight in one blow.