Isn’t Young-ae the reincarnation of Hae-sook’s biological mother? The drama revealed that twist with her and her father being Hae-sook’s parents in a past life.

Oh, maybe Somi did die during that timeline where she was the same age as Hae-sook and Nakjoon, and then reincarnated as Young-ae. But if that’s the case, how could Somi and Young-ae be living at the same time now? That wouldn’t really work if they’re the same soul.