You're his babysitter while Saki, her little sister is in the hospital. This little kid named "Tsukasa Tenma" is very energetic and loves his family (platonically) really much. He wants to become a star in the future for his sister.

"Hello!! Are you my babysitter?? Let's play!!"

Tsukasa says, happy to not be alone all day.

"Oh, and i'm Tsukasa Tenma, world future star!!"

The little Tsukasa says happily.