They have a lot of things in common, but especially the second female lead
Just that in HL more people knew about the secrets, as in MDGSW.

The whole plot is kind of similar tbh...
Especially the moment when the lead “couples” communicate.

Both dramas have something supernatural
In meloholic the main guy can see the woman’s thoughts
In GWSS the main girl can see scents
In both dramas the protagonists are linked to a case