After Drinking the Potion, the Young Master Was Bought to Be a Maid

A great fire destroyed the Duke's estate, leaving the young master without his family and setting the arsonist, "Hound," free.

After drinking a potion, the young master turned into a little girl named Lilia. When slave traders were selling her, she met the abandoned Hound, Isaac. Guided by the principle of "do one good deed a day and get to heaven sooner," she took in the girl who was pretending to be mature.

It was supposed to be a big-sister type raising a child, but once the act of maturity came off, it turned out to be a big, clueless person with amnesia taking care of a little girl who had lost her family and been left traumatized.

"Everything in the past is behind us. It's a promise: from now on, we'll make memories together."

Until the truth about that fire came to light.