Season 1 of Moon in the Day premiered on November 1, 2023.

Han Joon-oh is a leading South Korean celebrity. He is stunningly good-looking and tall, but is secretly plagued by an inferiority complex that leaves him permanently insecure. One day he is hired to appear in a public service video. But the shoot goes horribly wrong, and Han Joon-oh is involved in a potentially fatal car collision. He is only saved by the quick thinking of a female firefighter named Kang Young-hwa, who pulls off a heroic rescue.

Han Joon-oh’s representatives hire Kang Young-hwa to work as the star’s personal bodyguard, recognizing her incredible talents. But when Han Joon-oh awakes from his stupor in hospital, he has changed completely – as his body has now been possessed by the spirit of a nobleman from ancient Korea. This nobleman, named Do Ha, was killed by his beloved wife Han Ri-ta – and the vengeful spirit is on a single-minded quest for retribution…