There are some gaps in the story, for example it's not well told who travels when, where and why. I also find the story about InTouch very flat and where does sin's friend randomly come from in the last ep?
However, we are rewarded with some nice moments and as viewers we are involved in the writing process of a novel, where they get the inspiration etc. from. I also think the idea of visualizing the group chats is great, unfortunately it didn't work out so well (why do they always wear such random costumes and look very childish?).
The acting is solid to good, the performance of per (inTouch) really bothers me. Two points really convinced me: the acting of the main couple (since it was the first series of the two that contained more than just soft scenes and everything fit very well) and the performance of the “second” lead couple o+p.
Overall I would probably give it a solid 5.5.