I don't understand all the other negative reviews about this short and sweet drama. For me, a drama is really beautiful, if it can make my heart feel something: happiness or sadness. This drama did both of that. It felt like I was in pain when the actors were crying and I am so grateful that they were happy in the end.
Just think of it as a movie, instead of a drama so that you don't go in with the expectations and later say that everything was squished into about 3 or 4 hours.
The 4 episodes were more than enough to get their story across and make you root for the main leads.
So, I hope you give it a chance.