I'm sure all you Sones watched this drama, didn't you? Yoona played the main lead in this drama and played two different characters. It was a little slow in the beginning for me as it showed a love story of the parents. (Yoona and Jang Geun Suk played the parents as well as the kids of the parents). However, I always find it really freaky when dramas make the kids look EXACTLY the same by using the same actors and actresses. It is understandable that they want to show the connection between the kids and the adults, but that is just ridiculous and a bit confusing.
In the 70's, Seo In Ha (Jang Geun Suk) and Kim Yoon Hee (Yoona) fell in love. However faced with the obstacles then, they did not marry each other. In the end, Seo In Ha marries Baek Hye Jung (which if I am not mistaken, was actually Yoon Hee's friend). Seo In Ha and Kim Yoon Hee end up with their own families and ended up having children.
Then in 2012. (The parents are older and different people are playing the role now. Yoona and Jang Geun Suk now play the children. Yoona is the daughter of Kim Yoon Hee and JGS is the son of Seo In Ha).
Yoona is playing the role of Jung Ha Na and JGS is playing the role of Seo Joon.
The two met in Japan and it was pretty amusing. They end up falling in love with each other. However, they couldn't just have a nice and easy love story. They faced a lot of problems. One thing was that there were other characters who crushed on the main leads, so that led to some sweet/annoying moments when you realized that this other character liked the leads. The next thing that made it difficult for this couple was the fact that their parents saw each other again and rekindled their love for each other again...AWKS, considering that the kids are dating each other. They have a lot of cute moments and they really cherished their time together. It was also cute how they were doing what they liked to do. Ha Na was a gardener because she loved plants and Seo Joon is a well-established photographer. However, because Ha Na wanted her mother to be happy, she wanted to keep their relationship a secret and he agreed however, it only led to them hurting more as they couldn't be together.
Then, another thing, Baek Hye Jung who is the mother of Seo Joon...let's just say, she was extremely hateful towards both Ha Na and Yoon Hee. She disliked the fact her son was dating Ha Na who looked exactly liked Yoon Hee back in the 70's...I guess, she felt intimidated by the fact that she could lose her husband and her son to these women. So she was a little harsh on the mother and daughter.
There were its happy moments in the drama (even though sometimes it felt like it was dragging)
There were also its sad moments and thankfully ended with a happy ending