Here is a character chart made by @Korean___Dramas on twitter.
Link to the og post: https://twitter.com/Korean___Dramas/status/1652992010406744064?s=20

only after 2nd ep it's really interesting and confusing if Misook is real killer and what if not

 ginkgo_leaves:

By any chance, is it the remake of Taiwanese drama, ‘someday or one day’?  Thx.

Not that I know of. Time traveling is a trope used quite often so I don't think they have anything to do with each other.

 ginkgo_leaves:

By any chance, is it the remake of Taiwanese drama, ‘someday or one day’?  Thx.

There's a korean remake in the making but it's called: A Time Called You with Jeon Yeo Been & Ahn Hyo Seop!

The time travel in Someday or oneday was pretty complex . Compared to that this is straight forward. Still a fun show to watch.