The story has a similar foundation.
1. Both leads share a long servant-master relationship
2. the "servant" seems like he has feelings for his "master" but keeping it a secret
3. the "master" doesn't even realise how much he is in love with the "servant" until he gets jealous and feels like he is losing the other
The characters are similar on the level of Shu Nian is quiet like Kang Gook and the master bratty and keeps touching the other frequently just like Han Tae Joo. But Han Tae Joo is waaay nicer than Xie Yan