Must stay by his/her side

Looking for drama where the one of the main leads has to stay by the other's side for whatever reason, be it bodyguard or whatever. However it should be part of the plot, so ordinary secretary or partner or whatever doesn't count. Best if the reason why they have to stick together is secret. I hope you get what i'm looking for.

Thanks :)

Maybe...
Healer
You're Beautiful
The Master's Sun
Rooftop Prince