I have seen many reviews saying this drama was bad, it shocked me to be honest, I thourouly enjoyed this kdrama, yes it did in fact have many plots but it honestly made sense to me.

the mother was dying and wanted to spend time with her son, he did not move in bc his father was a cheater. during the process of all this he rented a room in the house and fell in love.

due to his mom dying, his dead biological father saved the ML so he could spend her last days dying in peace rather than grieving and dying from cancer.

with the vanishing throughout the show, I just interpreted it as his presence does not belong to this world because he was supposed to die.

Also his bio father probably had to use powers to revive him and made sure he had no injuries, he could’ve been weak and not able to keep him on earth too long hence the limit of 49 days.

although these plots were not explored properly and effectively as it should be the drama was truly beautiful and it made me ignorant to the fact that it was lacking in some areas.