just a speculation after watching the 4th episode, i think they may be related and they "share" the same father which is Mr. Do
also i can’t stand the mom and the grandfather, i am an empathetic person and my blood is boiling when i see how they treat Kang Bi O when he did nothing wrong, i even shed a tear at the last scene
also i can’t stand the mom and the grandfather, i am an empathetic person and my blood is boiling when i see how they treat Kang Bi O when he did nothing wrong, i even shed a tear at the last scene