All of the four pairs relationships didn't have any depth or whatsoever. Not even a proper build up was provided. If you thought this is about the sisters relationship then you'll be mistaken, it focuses mainly on their love interests and whatever comes with that. I found most of the characters were poorly written, they have the motivation of a first grader, even throwing a tantrum like one. Even if we considered the pairs relationships, all of them were underdeveloped. The romance failed and the family drama failed, not sure what else left to it. The performance was average at best, I've seen Chae Rim doing far better in other projects.