Most of the time people are mistaken about the three of them. Yes, they're definitely sisters however they're not triplets. They may have a lot of similarities especially in terms of physical attributes but when it comes to personalities they're different from one another.

CHARACTERS:

YuRi --  The oldest of the three Kim Sisters.

YoonA -- The middle child.

JooHyun -- The youngest.

The other characters will slowly unfold as the story goes..